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Last updated: 19 December 2008
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Last updated: 19 December 2008 |
This page documents astrophotography comments, tips, and photos. Contributions welcome. Be certain to see the other articles on the main Astrophotography page.
Subject: Astrophotography Tips Sent: Tuesday, December 16, 2008 11:21:15 From: Dave Arnold (d3arnold@yahoo.com) This is in response to the last Astrophotography Tips update on the 16th. I have no problem getting focus with my Nikon D80 with my etx 70. I use a #64st t adapter. Note the ST, this is important. If you go to opt you can find 2 #64 adapters. The st stands for short I think. The st version is very thin. Just thick enough for the two threads etx and t. I also have the other #64 which I found could not achieve focus on the 70 but it does work on 90+ etxes. I hope this helps. Regards and clear skies. Dave Arnold
Subject: Unable to focus when mounting camera to prime focus of Meade ETX-70 Telescope Sent: Saturday, December 13, 2008 17:02:04 From: Ray Ares (rlares@aresphotography.com) I have spent some time researching a problem I am having with no success and I hope you can help. I recently purchased a used Meade ETX-70 telescope. I am into photography and want to take some photographs of the moon, et al. I separately purchased a Meade #64 T-mount and Canon EOS camera adapter. I connected my camera and I cannot focus properly through the camera. I read some posts about measuring the distance from middle of the mirror to the eye piece and then comparing that to middle of the mirror to film plane and they should be similar / same. I am using a Canon EOS 1Ds camera (full size sensor). I have successfully focused on a object through the telescope/camera only by connecting the camera adapter to the camera and holding the camera against the telescope without the T-mount. The T-mount comes in two pieces a short section with the screw ring for connecting to the telescope and a separate longer extension that could go between the short section and the camera mount. Whether using both pieces of the T-mount or just the short piece, I cannot get any kind of focus, but the shorter section alone is better, but nothing is even recognizable when using it. Any suggestion on how I can fix this problem? One thing I thought is that if I can disassemble the short section of the T-mount, I may be able to connect the telescope mount directly to the camera mount and that combination might be short enough to achieve focus. Alas, it is either designed to not be taken apart or I simply don't know how to do it. Thanks for any assistance you can provide Ray AresMike here: The problem is the available focus range of the ETX-70 when coupled with some cameras and adapters. I had similar problems with my Nikon D70 DSLR and the ETX-70. You could try a prime focus adapter that goes into the eyepiece hole. It may (or may not) work. Hold the camera over the eyepiece and see if you can find a focus. If so, and if the camera body is roughly the thickness of your T-Ring from the eyepiece holder, then you could probably use a prime focus adapter.
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Thanks for the suggestion and the very quick reply. Ray Ares
Subject: ETX-90RA and astrophotography question. Sent: Tuesday, December 2, 2008 23:33:34 From: Alex Cordero (alex.cordero@gmail.com) I really enjoy reading your site but find it a little overwhelming at time because so much cool stuff. I thought I'd ask you this question as a shortcut to what I need. I have an ETX-90RA that I bought a few years ago. The astronomy bug has bit me again because I have a little more time for stargazing. I'd like to take some planetary and lunar pictures but is my ETX-90 sufficient for this? Will the motor track accurately? What do I need to get started. I have a Nikon coolpix that I purchased several years ago to photograph the moon through my Celestron C-8. But I'm getting rid of this light bucket because it's too big. I like the portability of my ETX. THanks. -- --- Alex CorderoMike here: Yes, you can do some astrophotography with the original ETX (now known as the ETX-90RA). I started with the ETX in 1996 and did some planetary, lunar, and DSO astrophotography. I originally used a Pentax Spotmatic 35mm SLR and a Casio QV-10 digital camera. I later upgraded to a Ricoh RDC-4200 and then to a Nikon Coolpix 995 digital camera. (I now use a Nikon D70 DSLR.) You will be limited to short exposures except for piggyback photography. But that doesn't have to be a limitation since, with software, you can "stack" multiple short exposures to make effectively longer exposures. I recommend starting with the moon and brighter planets. Depending on what adapters you have already have for your camera, you may or may not need anything else. If you do need adapters, see the Accessory Reviews: Astrophotography page. For more on astrophotography, see the Helpful Information: Astrophotography page.
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Thanks for your prompt reply. But is the ETX's motor accurate enough to track sufficient for astrophotography? Or do I need anything else?Mike here: Few telescopes that you could afford will track accurately. That is why there are off-axis guiders (for higher-end telescopes) and people use short exposures. For piggyback with a wide angle lens you the telescope will track accurately for several minutes (if correctly polar mounted and aligned). For prime focus, afocal, or eyepiece projection photography you will typically be limited to exposures of less than a second to a few seconds, depending on many factors.
Subject: can you autoguide with the 90PE Sent: Wednesday, November 19, 2008 11:19:54 From: mike (primeevil51@hotmail.com) Is it posible to autoguide with the etx 90pe scope,. I was thinking about picking up the orion autoguider that is $250. I also have maxim but I am still learning it. i know they have an autogider program. Thanks. MikeMike here: Yes, it is possible. The Meade DSI can do that as can some other guiders. Don't know about the Orion works with the AutoStar.
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how would i be able to or can you point me in the right direction to learn how. thanks MikeMike here: Start by reading the manual for the Orion autoguider when you get it. Or ask Orion tech support.
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thanks! Mike
Subject: ETX astro-photos from Shanghai Sent: Sunday, November 16, 2008 01:46:14 From: John Wells (jfw@jfwhome.com) Hello from Shanghai, China! I'm a relatively new owner of an ETX-125, and have been trying my hand at astrophotography, which as you can imagine, presents fairly unique problems as I live right downtown in this smoggy and light-polluted city of 20 million people! To make matters worse, my observatory is a balcony with only about a 40 degree field of view. I recently bought a Canon EOS 450D and tried my hand at prime focus astrophotography. Orion just happened to be passing over my limited slot of sky. The first picture is around a ~10 second exposure. The second is a few exposures of 20 - 30 seconds hand-stacked. I found that 20-30 seconds was about the limit before drive tracking errors set in - most 30-second shots showed trailing. (Unfortunately, I couldn't polar align as my slot of sky doesn't include Polaris -- I tried with a compass but the tracking was way off. In fact, this was the first time I was able to align my ETX at all, even in Alt/Az mode, as it was the first time I could identify two bright stars in my field of view -- Rigel and Sirius, to do a 2-star alignment!). You're welcome to put these pics up on your gallery to show what can be done even in the most unfavourable of conditions. I'd like to ask your advice, however -- I'm really interested in doing longer exposures using guided piggyback photography. I was thinking of repurposing a webcam to do guiding corrections via software, and DIY-ing a piggyback mount. However, I did a "test" 10-minute unguided shot of a blank piece of sky at a 50mm focal length, and found that the light pollution made the shot an orange-white colour with the aperture wide open. Is piggyback photography going to be out of the question for me, or will smaller apertures help? Perhaps when guided properly the camera will be able to see much more contrast between the stars and the light pollution? I don't have any telephoto lenses yet, so this knowledge will help me choose one -- obviously a 200mm "fast" lens is very expensive indeed -- but if I have to stop down to f/4.5 or above anyway, I will be able to get away with a much cheaper lens. Primarily, I'd love to be able to capture some galaxies through longer exposures. I look forward to any advice you have. Best regards, John
Subject: Re: ETX105 Pictures / Experience! Sent: Monday, November 3, 2008 09:11:20 From: Jason Melquist (jmelquist@gmail.com) quick followup Q: to your knowledge, in the 30sec to 10min range, is light collection in CCDs roughly linear? e.g. would five 1min exposures give nearly the equivalent exposure as a single 5min exposure (in terms of light collection)? if so, then it's a win on 2 fronts: "star smear" and noise reduction (given you let the CCD cool between shots)! Sorry if all this sounds a bit remedial, but i'm ramping up! thanks again, Mike!Mike here: Generally, individual exposures when stacked yield longer effective exposure times. And you get the benefit of reduced noise, reduced sky fog, and reduced tracking problems.
Subject: ETX Vignetting with 35mm camera Sent: Sunday, October 19, 2008 17:47:14 From: Robert A. Genna (laserbase@verizon.net) I know this is old news, but I have tried over 5 different 35mm cameras with my ETX90 plus Meade T-64/camera T-adapter and the vignetting at the viewfinder top is constant on all of them. Over 1/4 inch of the image is missing in the viewfinder top. Meade claims in the literature that the entire 35mm viewfinder is filled with the ETX90 used in this way. I will call them tomorrow and ask which 35mm camera to purchase. Would you have any additional information on this problem? Thank you. RobertMike here: Have you tried without the T-64 extension? It separates. Some camera/telescope combinations may work better that way.
Subject: ETX 90 Back Cell Adapters Sent: Wednesday, September 17, 2008 09:42:39 From: Johnson (fwjohnson47@wcc.net) I have been searching for an adapter to fit the rear cell on my (super great) ETX-90EC. In my research, I have found the following items: Meade Back Cell Adapter #07036 Meade Eyepiece Holder #9135 Meade Eyepiece Holder #07182 I have a CCD that fits the regular 1.25" holder and I want to attach it to the rear cell rather than put it in the eyepiece holder. That way I can leave an eyepiece in the scope as well as have the CCD ready when I center an object. Will the Eyepiece Holder #07182 fit the ETX or do I have to buy the Back Cell Adapter #07036 and the Eyepiece Holder #9135. Fred Johnson San Angelo Astronomy AssociationMike here: The Meade Eyepiece Holder #9135 and Meade Eyepiece Holder #07182 fit the standard SCT rear port but not the ETX rear port. Using the Back Cell Adapter #07036 for the ETX will allow SCT accessories to be used at the ETX rear port. Alternatively, you can use a "visual back" for the ETX; see the Accessory Reviews: Showcase Products page as well as the Accessory Reviews: Miscellaneous page. Note that the Shutan one is no longer available from Shutan; as to the Scopetronix model you might want to read the articles on the Other: Editorial Page for info on Scopetronix.
Subject: Suitability of ETX 80 AT for piggyback astrophtography. Sent: Tuesday, August 19, 2008 13:55:10 From: John Harding (jharding22@o2.ie) Having seen some amazing amateur guided astro photos I would like to attempt some myself. I've owned a Canon DSLR for a number of years and have some good lenses. I've kind of gotten bored of star trails and I'm looking to progress. I was considering buying an EQ3-2 mount with dual axis drives for this purpose. However I believe that the ETX 80 will track the night sky objects in the same way (RA, Dec ?), straight out of the box. I was wondering if you could point me in the right direction, and possibly give me an idea as to the maximum length of exposure (with accurate tracking) the ETX 80 would allow? Would the weight of the DSLR set up mounted on the scope hinder the tracking accuracy? Best Regards, John Harding, Ireland.Mike here: If you mount the ETX in polar mode (not possible with the supplied #882 tripod) you can take exposures of many minutes without trailing. In Alt/Az you can take shorter exposures (seconds) and then "stack" them for effectively longer exposures. As to the camera weight, it might be a problem in some orientations. I tried using my Nikon D70 DSLR on my ETX-70 and there was slippage. Adding a counterweight system (see the Helpful Information: Astrophotography page) can help reduce that problem.
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Thanks for the speedy response. I'll have a look into alterative tripods for the ETX 80 that will allow polar mounting. Keep up the good work on the website, its an excellent resource!Mike here: The Meade #884 is a good ETX tripod for polar as well as Alt/Az.
Subject: Focusing ETX-70 with T2 Adepter Sent: Wednesday, July 30, 2008 00:20:10 From: Thorsten Imme (imme@sdh-training.com) Hi Mike and thank you for all the information on your web-site! I have an ETX-70 and a Canon 450D (Rebel) camera. I just purchased a Soligor T2 adapter to be able to try some astrophotogtapy. But however I do, I cannot focus using the adapter. Is there a trick I don't know about or is it not possible to use a digital SLR together with the ETX-70? Kindest regards Thorsten Imme SwedenMike here: If you can not focus it is probably due to there being insufficient "back focus" with the adapter + camera. What camera adapter are you using with the T-Ring?
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Thanks for your fast answer! Sorry to bother you, it was just a beginners mistake. I was thinking a bit on this problem this morning and found out that there was one lens missing. Looking into the adapter, I found that I could place an eyepiece inside it. Trying to do so it resolved the problem. Now there is no problem focusing. This will be so fun!!! I'm waiting for Saturdays solar eclipse. I live in southern Sweden, so it will just be a 30% coverage of the sun, but I hope to get some nice pictures of it anyway. I got a solar filter for the ETX-70 from Germany and now I'm just hoping we don't get an overcast day! Kindest regards and thanks again ThorstenMike here: With the eyepiece you are doing eyepiece projection photography. Some adapters allow for that. Without the eyepiece you would be doing prime focus photography.
Subject: D80 noise Sent: Sunday, July 27, 2008 13:59:42 From: MICHAEL HOUSTON (mhouston6@cox.net) Last night I tried to do a four minute piggyback shot of the milky way. I got lots of ugly purple noise in the upper corners of the image. The lower right corner stuff I believe to be some light pollution from a city in the distance. Any Ideas on how to fix this problem? Thanks, Michael Houston
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Would this get rid of the detail o the picture? I have seen software that gets the picture out with the noise. Is it possible to cool the sensor, or at least the region of the camera that the sensor is located? Thanks, MikeMike here: You can cool the camera (somewhat; just don't over do it or you could damage something). Some camera owners have been known to put the camera in the freezer for a short time before taking exposures. I haven't done that and don't intend to. Noise reduction (in camera or with software) will remove some details in those areas with noise. However, those areas already have reduced detail due to the noise. You can also taken several shorter exposures and "stack" (combine) them in software (Mac OS X: Lynkeos, Keith's Imager Stacker; Windows: Registax, AstroStack).
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I will check out the stacking software. Thanks, Mike
Subject: questions about imaging set up with ETX-90 Sent: Wednesday, July 23, 2008 08:52:29 From: Eric (eddot1103a@verizon.net) You have a wonderful site and I have been following it off and on for years. I did some searching for the information I'm seeking, but I was unable to pin down specifics, so I was wondering if you might be able to help. I have been trying to use a Canon Digital Rebel DSLR at the ETX-90's prime focus for terrestrial imaging, mainly birds, but I am running into problems, mainly the very slow nearly f/14 focal ratio. I have been thinking about trying to use a Meade f/6.3 focal reducer in between the scope and camera, however some tests done by a friend are showing vignetting with the ETX/ FR/ Rebel combination. The field is indeed reduced, but so far the vignetting issue isn't solved. Do you have any suggestions for vignetting reduction/ elimination? Thanks in advance, Eric ToddMike here: Yes, vignetting will occur with the Meade SCT focal reducer. You might want to check out some others as discussed on the Accessory Reviews: Astrophotography page.
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Thanks for your fast response. After more researching your recommendations at your site, the Shutan Wide Field Adapter looks like a possibility to use with my Canon Rebel. I see the pics you took with the WFA followed by the OPT camera adapter, but I can't tell whether or not you had vignetting, although the field does look wider. Since I'd primarily be doing birding, the least vignetting and coma at edge of field are pluses. Thanks, EricMike here: You will see some coma at the edges with the wide-field adapter. I don't recall any noticeable vignetting. Software like Aperture 2 would remove any vignetting easily.
Subject: Re: Have you heard any thing about Digi-Kits? Sent: Sunday, July 6, 2008 08:58:46 From: carl cohen (carlcohen@optonline.net) I ordered a Digi-Kit from CNC via the web (no telephone support). There were no problems at all and actually they were very professional. They sent me an email receipt and the item came very quickly, protected in bubble wrap. They even sent me an extra gift, a really nice astronomer's multi-tool pocket knife with a compass and a red flash light. I have not had a chance to use the Digi-Kit yet, but it looks like it is made well and fits my camera and eyepiece as documented on their web site. I plan to use on my ETX 125 and PST. Any suggestions on what settings I should use on the camera, which eyepieces are best or software to use? Thanks, CarlMike here: For starters I would recommend using your lowest power eyepiece on a bright object like the Moon. That will let you learn how to actually use your camera for astrophotography. Try letting the camera set the exposure. Use a moderately high ISO setting to keep shutter speeds short but not so high that you get a lot of image noise. For afocal photography you focus the eyepiece to your eye, mount the camera with its lens set for infinity. If the camera has a macro or zoom lens function, try using that to enlarge the image in the camera. If your camera has a self-timer use that to avoid enducing vibrations when pressing the shutter release. If your camera still creates blurring during the exposure you will likely need to use the "hat trick" method, which requires that your camera have a "bulb" shutter setting. Cover the telescope objective with a "hat" (I use a piece of black cardboard), open the shutter, slide the "hat" away from the objective for the length of the exposure, then recover the objective, and finally close the camera shutter. As to software, there are many possibilities. You can start with what's included with your computer (such as iPhoto on Macs). Any image processing software will let you make adjustments that can improve (or ruin) astrophotographs. Beyond that there is stacking software but wait until you get more experience using your camera for astrophotography. For a lot more information on astrophotography, see the Helpful Information: Astrophotography page on my ETX Site.
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Thank you for the information. I will try it during my next clear night! Carl
Subject: RE: Baader Planetarium UV-IR-Cut Filter for ETX70AT Sent: Monday, June 30, 2008 21:41:07 From: cuco argaez (acuco@hotmail.com) Wow! Thanks for the prompt response. I tried taking pictures without the UV/IR filter and I got great pictures of the moon (without manipulations or stacking) but Jupiter looked only as a bright object with no definition or color. Is that all I am going to get? Would it be better with the Baader filter? Hope I am not bothering too much. Thanks againMike here: It sounds like you are overexposing Jupiter. Reduce the exposure settings.
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Thanks for all your help and dedication! You are amazing!
Subject: Baader Planetarium UV-IR-Cut Filter for ETX70AT Sent: Monday, June 30, 2008 20:24:59 From: cuco argaez (acuco@hotmail.com) First of all, thanks for your outstanding website. It has been enormously helpful while taking my first steps into astronomy. I have a ETX70AT, a Meade 126 (2x) Barlow, and a SPC900NC camera (with an adapter). Since I took the infrared lens (filter) off the camera when I installed the adapter, do I need a filter to compensate the loss for astrophotography? I am considering buying a Baader Planetarium UV-IR-Cut Filter, which I would use it to take pictures of the planets and some of the brighter messier objects. Would you recommended it? Would it make a noticeable difference? Thanks in advance for your response and please continue the great work Cuco ArgaezMike here: Removing the IR filter will not likely change your images much. In fact, with some objects the images could even be improved. I would suggest trying it without the filter and see if you like the results.
Subject: Can Meade ETX-80AT-TC be used for short exposure time astrophotography? Sent: Friday, June 6, 2008 02:13:46 From: szilard.csizmadia@dlr.de I would like to ask you about Meade ETX80AT telescope. I need for a portable telescope which is as portable as possible, so it should be relatively easy and small. I would like to take digital pictures with relatively short exposure times (let's say max 3 minutes). Can Meade ETX80AT be used for this purpose? I feel that equatorial mount would be better but it is bigger and more expensive. This telescope has an alt-az mount. What is your experience with its guiding? How precise is its guiding? Does it disturb this kind of photographic work? Thank you in advance. Szilard CsizmadiaMike here: Through the telescope exposures of several minutes will typically require some sort of guiding correction (with any telescope). Plus in Alt/Az mode you will get "field rotation" on the images over a period of minutes. Using a polar mount will avoid the field rotation. However, you can take multiple exposures of shorter duration (to avoid trailing or field rotation) at high ISO settings and stack them using software.
Subject: Specifications of camera adapter fitting on rear of ETX90EC Sent: Friday, May 2, 2008 14:20:15 From: James Haight (jimhaight@hotmail.com) What are the pitch and diameter in mm of the camera adapter fitting on the rear of an ETX90EC? I'd like to fabricate an adapter for my JVC GZ-MG155 camcorder, which has a 30.5mm filter thread. Thanks and regards, Jim HaightMike here: I searched the Site for "rear port thread" and found one reference to this that said: "It turns out that the back of the ETX is a 1.375 x 24 thread which is the same thing that bicycles use for both the rear freewheel and the left side of the bottom bracket. I was able to use a bicycle lock ring glued to a 1.25 ID tube to make a decent adaptor." That's all the specs I have on it. Keep in mind that if you attach a camera at the rear port you would need to remove the camera's lens. If you can not remove the camera's lens then you would have to use an eyepiece and do "eyepiece projection" photography. Also, you might need to use a counterweight system, especially with a camera at the rear port. For more on counterweights see the Helpful Information: Astrophotography page.
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