Weasner's Astrophotography Tips Page

ASTROPHOTOGRAPHY - TIPS

Last updated: 17 April 2013

This page documents astrophotography comments, tips, and photos. Contributions welcome. Be certain to see the other articles on the main Astrophotography page.

Subject:	CCD , Filter wheel and  f3.3 reducer no focus
Sent:	Saturday, April 13, 2013 12:27:35
From:	simon wihl (simon_wihl@hotmail.com)
I have an ETX 125 PE and have attached a DMK camera to a filter wheel
and then the Meade f3.3 focal reducer to the back port of the telescope
but don't seem to be able to focus. I have taken out the filter wheel
and all is ok. Does  the addition of the wheel put the CCD out of the
focal range of the instrument or is there another way to do this ?

Regards.
Simon.

Mike here: There is limited focus travel on the ETX, so it is not surprising that the addition of a filter wheel along with the SCT adapter + focal reducer will not focus. You could try a focal reducer designed for the ETX (if you can find one).

Subject:	Cannot Focus DSLR Camera on ETX 90
Sent:	Monday, March 18, 2013 15:55:02
From:	GoodmanFandM (goodmanf@q.com)
As always I enjoy your site and the wonderful images you post, from your
Cassiopeia, observatory.

I am always amazed at what the IPhone ( and other cameras) can image,
and the great care and patience you apply to your craft.

Now to my issue. I have a Pentax Kx DSLR camera, with the 18-55mm and
55-300mm Pentax lenses.

I have tried, unsuccessfully, obtain focus, with the camera attached to
the eyepiece holder (no eyepiece), and using either camera lens.

Although I have the Meade 1244 Electric Focuser, I cannot get focus in
either direction of focus travel. I temporarily removed the electric
focuser and used the large brass gear to attempt focus. All to no avail.
When I turn the gear fully CW  (to the mechanical stop), I get closer to
a possible focus, but I would need much more travel CW (not possible). I
have tried both Landscape and Macro modes, as well as full manual focus.
Nothing brings the images (The Moon or Jupiter) into focus. My homemade
adapters have a depth of about 1 inch between the camera lens and the
eyepiece holder. I have tried many lens magnification ranges (both
lenses trying the full range) and no improvement.

What suggestions might you have? Thank you, as always-Fred and Happy
Holidays, coming up soon.

Mike here: From your description it sounds like you are making a common mistake: using the camera lens when you shouldn't. See the article "Astrophotography Types" on the Helpful Information: Astrophotography page on my ETX Site to learn more about imaging with cameras.

And:

Thanks again, Mike, for the speedy reply. I guess I must use either
eyepiece projection(no camera lens?) or afocal (both camera lens and
telescope eyepiece?). I also have a Panasonic Lumix FZ-47 mega zoom
camera. It has too much magnification (even at the lowest
magnifications), to use with the afocal method (way too much vignetting)
and since the lens is fixed, I am out of luck, also with eyepiece
projection. Blessing to you and your family.

Mike here: With removable lens cameras you can do prime focus, eyepiece projection, or afocal photography. However, not all cameras will focus with all adapters on all telescopes, so your mileage may vary.

Subject:	Meade Focal Reducer and ETX90 for Photography
Sent:	Tuesday, March 5, 2013 07:49:03
From:	santiago.vallee@mdlz.com (santiago.vallee@mdlz.com)
My gear list is as follows.
         ETX90
         #64 T Adapter
         Canon 1000D (In US is the Rebel XT... I think)

And the list of gear continues, but these are the parts intervening on the issue.

I am starting up on astrophotography. Last January I was able to take
prime focus photos of the Jupiter occultation (unguided, but excited for
the success!), so during the summer I decided to go for wide field
photos with my camera lenses and tripod.

I wanted to return to the prime focus and read that a Focal Reducer is a
must, but I could not find much info regarding the compatibility with
the ETX90. I see that MEADE offers an ETX to SCT back cell thread
adapter, but I am afraid that I will need to change the #64 for a SCT T
Adapter...

Any insight in this regard will be appreciated.

BTW: I loved the Dr Craig ETX TuneUp articles, that I consolidated all
the text and photos (as well the scopetronix parts as annexes) in a PDF.
Let me know if you want to have it, and I can forward it to you for
inclusion in your site.

Thank you so much for your help and for the ongoing effort to maintain
the ETX Site for all of us.

Best regards!

Santiago Miguel Valle

Mike here: First, a suggestion. Mounting a camera at the rear port of the ETX creates two significant problems: balance and interference from the ETX base. If you mount at prime focus using the eyepiece port you avoid these problems. I use the OPT Camera Adapter (see the Accessory Reviews: Astrophotography page). As to a focal reducer, there are several (older) ones discussed on the Accessory Reviews: Astrophotography page. Some ETX focal reducers will mount at the rear port and some like an eyepiece. A focal reducer will make the ETX a faster optical system and yield a wider field-of-view (FOV). The wider FOV will reduce the image scale, making tracking errors less noticeable (but still present, depending on how long an exposure you do).

And:

Thanks Mike.  Will check the "eyepiece port" options then.

Best!

Santiago Miguel Valle

Subject:	Jupiter's moons
Sent:	Thursday, January 10, 2013 12:17:10
From:	Terry Godfrey (terry.godfrey@mypostoffice.co.uk)
Having had some recent success using the Meade LPI and its software, I
thought I'd try acquiring a short video clip of Jupiter on my Canon 600D
and simply using Registax to align and stack the individual frames.

The overexposed image above (flipped to give an erect image) clearly
shows 3 moons, however from
http://www.nakedeyeplanets.com/jupiter.htm#jupmoons  at the time the
video was made (18:06hrs UT on 9th January 2013 at Oxford UK) the fourth
moon, Europa, should have been visible emerging from behind and to the
left of Jupiter. There was still no sign of Europa 30 minutes later when
it clouded over.

A  better image (flipped) was obtained in the same way but using a
barlow x2 on my Meade 125EC. Video frame exposure was set to 1/30" sec
and ISO 1600. Some 1200 frames were aligned and stacked using Registax.

From the nakedeyeplanet.coms website, Io is just visible to the right
but there is no sign of Europa to the immediate left of Jupiter -
Callisto and Ganymede were off screen to the left.

The quality seems much better using the Canon EOS 600D when compared to
the LPI.

Any idea why the website's  data did not agree with my actual sighting
or perhaps I have misinterpreted the site's data?

Regards

Terry Godfrey, Oxford UK

Mike here: The web site data agrees with Pocket Universe on my iPhone for about the same time:

In looking at your overexposed image, I can almost convince myself that the moon is there. The clear image of Jupiter might show the moon if you did some "levels" adjustment in photo editing software.

And:

Thanks Mike.

I screwed the levels right up in Photoshop and indeed, a faint spot did
appear in the "right" place.

Regards

Terry Godfrey

Subject:	USB and HBX extension cables
Sent:	Friday, January 4, 2013 12:18:16
From:	Terry Godfrey (terry.godfrey@mypostoffice.co.uk)
Thanks for the advice (My Astro-photography question posted on 01/04/13)

I will try 10 metre extensions to both USB and HBX cables which should
be long enough.

I note that a straight 10 metre CAT cable used in place of the Meade
cable would kill the Autostar due to the pin connections not being
reversed so I will use a 10 metre CAT cable and an inline connector with
the existing Meade HBX cable to maintain pin connections.

Regards

Terry Godfrey

And an update:

The 10 metre #497 HBX extension cable and 10 metre LPI USB extension
cable appear to work fine!

Subject:	Astro-photography Tips page
Sent:	Thursday, January 3, 2013 04:00:15
From:	Terry Godfrey (terry.godfrey@mypostoffice.co.uk)
I was interested in your communication with Robert (29th December 2012)
re. general night sky photography on the Astro-photography Tips page

In December 2012 I had hoped to catch Geminid meteor trails on camera
but instead of leaving the shutter open for several minutes with a
static camera I decided to piggyback my DSLR on my polar tracking Meade
125EC using an intervalometer to repeatedly take 2 minute exposures in
the hope of catching a meteor against a reasonably bright star field
rather than star streaks.
Unfortunately I didn't catch any meteors before the camera lens dewed
over but thought Robert might be interested in the result of a typical 2
minute tracked exposure.

Photo details:
Canon EOS600D, 18mm @f4, ISO 400, exposure 2 minutes.

Orion is in centre with Jupiter above the Hyades and to left of the Pleiades
The reddening in the sky is from the city lights of Oxford.

On a separate topic, I have been trying some astro-photography with the
LPI on my Meade 125EC.
Finding it rather cold sitting beside my laptop next to the scope, what
is the maximum extension I could attach to the LPI USB cable and also
the 497 handset control cable to enable me to view the LPI image and
make tracking adjustments from indoors?

Below is my first attempt at Jupiter

Regards

Terry Godfrey

MIke here: USB cable lengths can run very long, but there is a limit and a power issue. Do a search for "USB length" on the ETX Site and you'll get several pages that discuss the LPI USB cable length. The HBX cable can also be very long; see the article "Long AutoStar Cable" on the Helpful Information: AutoStar Info page.

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