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Last updated: 29 March 2009
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Last updated: 29 March 2009 |
This page documents astrophotography comments, tips, and photos. Contributions welcome. Be certain to see the other articles on the main Astrophotography page.
Subject: Astrophotography Sent: Sunday, March 29, 2009 16:52:11 From: Harry Krantz (hrkrantz@earthlink.net) I have a Meade Etx-80-At tc and an Imaging Source DBK-21AF04 ccd camera with Astro IIDC software Last night I used it for the first time and when I tried to focus on the moon I ran out of tube, as it was all the way out. I tried moving the camera farther out but it made it worst. Is there anything I can do to fix this problem? I've heard of focusing lenses but I don't know what they are. Harry v This is what it looked like v
Subject: Buying additional flip mirror on etx125 with barlow and ccd camera to much strain on drives? Sent: Thursday, March 26, 2009 23:00:32 From: Jennifer Williams (j.williams75@optusnet.com.au) My Wife and myself own a etx125 and a gstar ex ccd camera with standard 1.25" nosepiece. we would like to know the best way to allow us to have both the camera and a eyepiece simultaneously, as we area having great difficulty finding the object on the screen. will the weight of the flip mirror and camera strain the drives of our etx125? Thanks for your time, Kind Regards, JamesMike here: I don't recall any Off-Axis Guider for the ETX. You could attach a OAG that works with SCTs but then you would need a SCT accessory adapter for the ETX. You would also likely need to add a counterweight system to avoid the strain on the drives and prevent slippage during GOTOs and tracking. There are several DIY tips on counterweights on the Helpful Information: Astrophotography page. One other thing to keep in mind when adding accessories to the rear port of the ETX: in Alt/Az mounting mode you will find that you will have limited movement in elevation as the accessories will touch the base at some point as you increase the elevation. In Polar mounting mode there is typically no interference between accessories and the base, but then you may have to contend with the OTA/base interference at low elevations, depending on your latitude.
Subject: Astrophotography Sent: Monday, March 23, 2009 11:58:43 From: John R. Tomawski (jtomawski@itasoftware.com) On a separate note, what telescope or Nikon Lens/Mount would you recommend for Astrophotography of objects such as M42? Currently I have a Nikon D70s camera for this application. Dark skies are an issue in Massachusetts, but I could always take a trip to New Hampshire or Vermont. Thanks again, John R. TomawskiMike here: I use a Nikon D70 DSLR for my astrophotography with my ETX telescopes as well as my 8" LX200-ACF. You can learn more about using the D70 on the Helpful Information: Astrophotography page. I have reports on my use as well as feedback from other users.
Subject: ETX 125pe and the ISS Sent: Sunday, March 22, 2009 18:36:50 From: User721401@aol.com (User721401@aol.com) I am, and have been, trying to photograph the ISS thru the ETX125. I am wondering if there is anyway to pre-focus the scope so when the ISS fly's by it will be focused or close to focus so I can manually track and shoot. I am either going to use the Nikon D70, a toucam, or the Meade DSI 2 pro... Forgive me if something is already posted on your web site... I failed to find any "tips".. DanMike here: Just assume satellites of earth are at infinity. So focus on a star, planet, or the moon.
And:
Thanks for the quick response. I have been trying for years to get it.. I hope this year is the year... Hopefully I will have something to send sooner then later. Dan
Subject: Solar Imaging / Photography with the ETX Sent: Friday, March 20, 2009 10:21:35 From: Brian Jones (bjones39@gmail.com) I have had a search through the site and the manual and am still unclear. I want to do some solar imaging / photography. I have a solar filter & the necessary T-mounts to fit my camera to the ETX. My query is two-fold. 1. The Sun does NOT appear in the Solar System menu, so you cannot GoTo the Sun. How do you align during the day so that the ETX will track the Sun correctly. I have an EC scope, so I have levelled the tripod, put the scope in the HOME position and then done an "Easy" alignment and simply pressed the "Enter" key when requested. Obviously, I cannot see any stars and obviously, the scope reports successful alignment. Is this the correct procedure for aligning during the daytime? 2. If the above procedure is correct, will the scope when correctly pointed towards the Sun with the solar filter in place (and the finder objective covered), track the Sun correctly. There are three tracking rates on the ETX - Sidereal, Lunar and Custom? I guess that Sidereal would be the closest - although the Sun's passage through the sky isn't as fast as the Moon, but it is faster than the stars? Any help would be great. Thanks in advance, Mike ArtMike here: Faking the alignment (as you did in step #1) is fine. It will be accurate enough for tracking the sun. However, it does assume you put the telescope in an accurate HOME position. Alternatively you could do the alignment at night and then put the AutoStar to sleep. During the day, with the telescope back in the same location (and position) as when you aligned, you will be even better tracking. Of course, you could always Polar mount the telescope, but then you would need to aligh the polar axis to the True North Celestial Pole. As to tracking rates, it is usually sufficient to use sidereal. Afterall, you probably won't be doing long duration photography of the sun.
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Thank you for the swift reply Mike. I have some painted dots on the patio for the feet of the tripod, so I can align at night (clouds & weather permitting) and sleep the scope, putting it in exactly the same spot in the daytime and slewing to the Sun. That sounds like an excellent idea! As you say, sidereal tracking for the Sun should be fine. I managed a photo today (the Sun looks featureless, just like a ping-pong ball) and the exposure was 1/100 sec at ISO 200 so, as you say, tracking shouldn't be an issue! Regards Brian
Subject: ETX 80 issue with afocal photography Sent: Wednesday, March 18, 2009 09:03:33 From: tom hess (tom.hess@hotmail.com) Last year I bought an ETX 80, and your site has been extremely helpful. I love this telescope, especially how it fits in my lugage when I take trips. I am a big fan, thanks for all of your efforts. Recently I purchased a celestron universal mount for afocal imaging. As the ETX has the ability to mount eyepieces in the 90 and 45 degree positions, and I have a couple of duplicated eyepieces I figured this was a no brainer. I set up with 32 mm eyepieces in both positions and mounted the camera on the 90 degree eyepiece. I used the 45 to focus and observe, and imaged through the 90. For my first attempt I decided on Venus. When I looked at the images from the camera, I could not reconcile the image to what I remembered seeing in the eyepiece. This aroused my curiousity so I did some simple testing. I pointed the scope a nearby cellphone tower and compared what I saw. I discovered the 45 degree erector prism is always going through the internal 2x barlow. This has caused all of my images for the evening to be out of focus. Now that I am aware of this, I can easily correct. As I have not seen this issue on your site, and it is not mentioned in the manual, I decided to let someone know. Is this a known issue or something peculiar to my ETX? Tom Hess Homestead, FLMike here: I'm not surprised that the two ports are not "parfocal", as they are not on the other ETX models. Since I don't have an ETX-80, I was not aware that the rear port was always using the Barlow Lens.
And:
thanks for the quick response. I wanted to let someone know as you can't plan for what you don't know about. keep up the outstanding work Tom.
Subject: Focal Reducer for ETX125PE Sent: Tuesday, March 3, 2009 06:01:36 From: tnspicerhome@comcast.net (tnspicerhome@comcast.net) Hi there. I love your site! Can you use a f6.3 focal reducer on the ETX 125 PE with the proper visual back adapter and diagonal . Thank you. Tim Spicer Davisburg,MIMike here: There are some focal reducers for the ETX reviewed on the Accessory Reviews: Astrophotography page. You MAY be able to use a SCT focal reducer with a SCT-ETX adapter. Depending on the adapter, reducer, and camera/imager, you may or may not be able to reach a focus or you may get a lot of vignetting.
Subject: DSLR application questions Sent: Sunday, January 18, 2009 17:02:53 From: Mike Pilgrim (mpilgrim@bellsouth.net) Mike, while I continue to learn how to accomplish imagery with my DSI, I also am intrigued by the apparent relative simplicity and quality demonstrated in your discussions using your Nikon D70 DSLR. Therefore, I request your direction and/or explanation of a couple of terms I have yet to grasp (i.e. Prime Focus vs. Eyepiece projection). My scope is the ETX-125 AT, so my questions relate to that particular instrument. When you reference Prime Focus, are you saying the camera is mounted with a T-adapter to the viewing port on the rear of the ETX? You mention that obtaining a good focus is trying in this configuration. Is this problem overcome by the application of the off-axis guider? When using Eyepiece Projection, I assume you are mounting the camera to view through the main eyepiece, but I get lost when you include the fact that there is a 15mm eyepiece involved. I have a problem envisioning this configuration. How is the camera mounted to the referenced eyepiece? Maybe I'm overlooking something, but have searched your site thoroughly for answers to those questions, or discussions of same in layman terms. Is that information published on your site? As a side question, let me ask if your new home site is located at the same place previously pictured where you ventured to your Oracle property to do your viewings? Within your home design have you incorporated an observatory? Just curious. Thanks for your dedication to the hobby, and for such a robust web site. Regards, Mike Pilgrim Boca Raton, FlMike here: Prime Focus astrophotography can be done at either port on the ETX (Classic models). I typically have placed my D70 DSLR at the top port but with the proper adapters, the rear port can also be used. However, the rear port is more problematic due the balance shift and interference of the camera body with the base/fork arms. Eyepiece Projection does use an eyepiece. However, don't confuse Eyepiece Projection with Afocal Photography. Eyepiece Projection "projects" the image onto the imager's focal plane (with the camera lens removed), whereas Afocal Photography has the camera lens (still attached) imaging the view through the eyepiece. For Eyepiece Projection, the eyepiece is held inside an adapter and the camera is attached to the end of the adapter. See the "OPT Camera Adapter" I discuss on the Accessory Revlews: Astrophotography page for one example of an adapter. Yes, that's the same location in Oracle, Arizona. As to an observatory, see my "Road to Oracle Observatory" blog listed under "Other" on my ETX Site.
Subject: question about astrophotography accessories Sent: Friday, January 9, 2009 10:38:16 From: Todd and Abbie Ausenbaugh (toddandabbie@bellsouth.net) I have recently purchased a DSI pro 2 for my ETX 125 PE .It has not arrived yet so I have no experience.I am considering a Knight Owl .5x focal reducer and Knight Owl deep sky + nebula filter.Also considering antivibration pads.Should I purchase any or all of these items?The DSI pro 2 will come with the color filters.Mike here: The focal reducer (if designed for the ETX) will be useful. Antivibration pads are nice but you can easily make some yourself; see the article "Tripod Vibration Suppression" on the Helpful Information: Telescope Tech Tips page. As to filters, you may wish to gain some experience with DSI astrophotography before getting additional filters.
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