Camera to telescope mounting - DPChallenge Forums

01/01/2008 07:05:25 PM · #1

So tomorrow a new toy is coming in the mail, a mount for my dads telescope.

neither of us have used one before so i was just wondering if any one had and if they could help me out with how to get best results.

01/01/2008 07:09:31 PM · #2

What kind of 'scope, and what kind of mount?

strangeghost

Canon EOS-7D

01/01/2008 07:11:02 PM · #3

Originally posted by chris48083:

Airfare to Wisconsin for a session with me and Kirbic. Bring your toys.

Sigma 150-600mm f/5-6.3 DG OS HSM | C

01/01/2008 07:14:15 PM · #4

I strongly suggest the following book:

Astrophotography for the Amateur

Although it was written around film photography, the rules and techniques still apply. It is a must have for anyone doing AP.

(I assume you are using your telescope for astronomic photographic and not terrestrial.)

BHuseman

Nikon D750

01/01/2008 07:45:26 PM · #5

What kind of scope and mount are you using? I have always wanted to get into this, I just haven't wanted to plop the money down on a scope and the Scopetronix adapter (that appears to be the best one I can find).

Originally posted by kirbic:

What kind of 'scope, and what kind of mount?

01/01/2008 10:11:59 PM · #6

Just be careful that the weight of the camera doesn't put too much strain on the tracking motors. Some of the higher end digitals can be a bit heavy for some older telescopes...which is why astrophotography is best suited with CCD cameras. Good quality ones are quite expensive.

01/02/2008 12:09:31 AM · #7

its an orion reflective telescope (not sure what the exact model is) with the skyview goto system. The mount is a orion t-adapter with a pentax mount (two seperate peices).

strangeghost

Canon EOS-7D

01/02/2008 12:41:47 AM · #8

Originally posted by chris48083:

its an orion reflective telescope (not sure what the exact model is) with the skyview goto system. The mount is a orion t-adapter with a pentax mount (two seperate peices).

The t-adapter is a mount designed to let you attach your camera to the scope to use the scope as a big lens. This is called "prime focus" photography and is the hardest type of astrophotography to practice. I promise you some severe frustration as you begin to explore this genre. You might also look into purchasing a "piggyback" mount, allowing you to put your camera (and lens) on top of the telescope and use the telescope's tracking ability to let you take long exposure shots of the sky that way. It's a bit easier to master for beginners. Prime focus stuff is HARD.

Good luck and let us know your results.

01/02/2008 01:34:16 PM · #9

I really didn't have all that trouble with prime focus. In fact, its the main method I use. Although, I do have a SC telescope with sufficient back focus, so it does make the job easy. The toughest part is the focusing...but do it on a bright star and you'll have no problems.

The toughest part is getting the scope aligned. If you are not aligned to the sky rotation, forget any long exposure photography.

The second method I prefer is positive projection, where you use the eyepiece (objective) of the telescope to project the image to the camera, without a lens. It is the best for high magnification lunar and planetary photography. You'll need a projection tube to cover the objective.

One last point, as far as alignment goes...use RA/DEC...DON'T use Altazimuth to track. In my experience, there is too much precision needed and therefore drift is a major factor. RA/DEC tracking involves only ONE motion, since you have aligned your mount to the equatorial axis. Though, this can take some time, but gives the best results for long exposure times.

Luckily, the new advanced editing rules allow for multiple exposures. This will be invaluable in getting some good shots of Saturn, Jupiter, and Nebulae. The best thing you can do it to take multiple SHORT exposures and overlay them. There are alignment software packages out there, but, if you are aligned well, you can align decently with photoshop. The benefit is that this helps to reduce exposure noise while maximizing the good image variability.

Paul

Originally posted by strangeghost:

Prime focus stuff is HARD.

Good luck and let us know your results.

01/02/2008 02:52:24 PM · #10

The telescope came with a piggyback mount, although I don't have a good lens for shooting (for whatever reason, when I zoom out to 300mm with my telephoto it goes out of focus even when it's at infinate, so I have to back off to 150-200mm).

Usually we don't have a problem aligning, although we do use altazimuth to track. We'll give RA/DEC a try, see what kind of results we get.

We aren't going to be able to drive out of the city tonight, so I'm worried about light pollution, so we might just end up shooting the moon.

Thanks for all the help guys, I'll post any worthwhile results tonight/tomorrow!

01/02/2008 03:13:42 PM · #11

Try using the piggyback mount with a WA lens & see what you get. Wide Angle night sky photography can be very rewarding. Try ISO 400 and about 3 minutes exposure. Stack 4 or more shots for some noise reduction.

01/02/2008 03:19:18 PM · #12

3 minutes is awful long for a digital that can do a max of 30 seconds. :(

sounds like I'll have to dig out the old film camera and find my shutter release...and buy some film...

01/02/2008 03:38:21 PM · #13

Originally posted by chris48083:

3 minutes is awful long for a digital that can do a max of 30 seconds. :(

sounds like I'll have to dig out the old film camera and find my shutter release...and buy some film...

Are you sure your cam doesn't have a "bulb" mode? If it does, then all you need is a remote release and you're set.

01/02/2008 04:03:03 PM · #14

oh snap! i completely forgot about that little setting! looks like im going to stop by the photo store to get an IR remote today!

FedEx just came and everything mates happy, now i just have to shovel snow to make room for the scope. =) (this is the part where i start getting all giddy and excited).

Should i leave my camera out with the scope so it cools down to the same outdoor tempature?

01/02/2008 05:03:26 PM · #15

Tip on the bulb setting:

To avoid shake...and yes, even if your camera has a mirror lock, the scope can still shake, have a piece of cardboard covering the scope just before releasing the shutter.

01/02/2008 06:02:38 PM · #16

Originally posted by PGerst:

Tip on the bulb setting:

To avoid shake...and yes, even if your camera has a mirror lock, the scope can still shake, have a piece of cardboard covering the scope just before releasing the shutter.

covering the scope? you mean actaully covering the end so it can stop shaking after you hit the release? i was planning on using a 3 sec. delay, possibly a 12 sec.

01/02/2008 08:13:17 PM · #17

Basically, the reason to cover the scope is to prevent light from hitting the sensor until the apparatus has stopped shaking. If your camera has a delay, thats even better.

Originally posted by chris48083:

Originally posted by PGerst:
Tip on the bulb setting:

To avoid shake...and yes, even if your camera has a mirror lock, the scope can still shake, have a piece of cardboard covering the scope just before releasing the shutter.

covering the scope? you mean actaully covering the end so it can stop shaking after you hit the release? i was planning on using a 3 sec. delay, possibly a 12 sec.

01/02/2008 08:37:43 PM · #18

Originally posted by chris48083:

Should i leave my camera out with the scope so it cools down to the same outdoor tempature?

You can do that... it actually will reduce noise pretty substantially in sub-freezing temperatures. Leave the lens cap on until you're ready to shoot to prevent frost, and keep the battery at room temperature; only install it when you're set to go. Keep a spare, charged battery warm, if you have one... you'll find that as the battery gets cold, it will appear to be discharge, but when warmed up again it will recover. Keeping one warm will keep you shooting.