First Try : Wide Field

[Tamtarn]

This is my first try at Astrophotography. Image taken with Pentax ist DL on a very ordinary Camera Tripod. No tracking of course.

Pentax SMC 50mm f2 lens - ISO 800 - one 15 sec shot.

Very basic processing in Photoshop.

Thanks to Doug (dugnsuz) for all your help in getting us started.

Any comments welcome.


David

[Gama]

Looks good.
If you like this type of imaging, look at getting a good lens. You have some astigmatism that prevents you from producing beautiful shots.
There should be some guys that will point you to a good lens, or maybe sell you one too.

[leon]

Nice effort David for a first attempt, those 50mm F/2.0 lenses are pretty good.

Cheers Leon

[jase (Jason)]

Good start David. The only tip I have is to stop down the lens a few notches maybe from F/2 to F/4. This will mask the optical aberations at the edge of field and overall sharpen the image. ALL lenses experience this issue, no matter how much you paid for it. The downside is you'll need to increase your exposure times to compensate for the reduced light.

[EzyStyles (Eric)]

great effort david and from just 15 sec! keep it up

[Tamtarn]

Thanks for the encouragement guys.

I've been waiting for the moon to rise later to get some shots and finally had the opportunity last night. This is one of the shots from that short session.

The exposure time was kept short because at this time we don't have a tracking mount. Have recently purchased a 135mm and a 200mm lens so we will need a tracking mount to get the best results from them.

I wanted to make sure I could take a reasonable image before investing in a mount.

OOPS Looks like more spending coming up !! Maybe an EQ5

David

[RB (Andrew)]

Well done David, what a great start.

[Ric]

Great first widefield David, thats one to be proud of.


Cheers

[Gama]

Originally Posted by jase

ALL lenses experience this issue, no matter how much you paid for it.

The reason they are expensive is exactly for these reasons. The professional lenses are corrected for many distortions. This is why the cost an arm, leg and 4 fingers. They produce huge corrected fields and near pefect color alignment.

[Geoff45 (Geoff)]

David
Something else you could try would be to take 5 or 6 such images and stack them.
Geoff

[Diamond Rose]

Cool pic, David, especially from 15 secs.

If you stopped the lens down to F4 how long would the exposure need to be? I would like to try catch an image like this on my Nikon F75.

~ Bruce

[Tamtarn]

Thanks Geoff

I have now taken 5 raw images of the same shot with 3 dark frames on the same settings as before. All I need to do now is work out the best way to stack, align and process them.
What program would you suggest for stacking and aligning.

David

[Tamtarn]

Hi Bruce

It depends whether you have a tracking mount or a basic camera tripod.
When I stopped down to f4 I had to increase iso to 1600 and time to 30sec.

As these shots were taken on a standard camera tripod without tracking, there was more noise and more stars were elongated.

Our EQ5 mount with dual motor drives arrives tomorrow, then I will be able to lengthen exposure time.

David

[74tuc]

Nice pic David - I wouldn't complain about it!!

What interests me is the hint of nebulosity - reddish bits among the stars.
You can see star clusters and the colour of some stars - very nice.

Take a longer tracked exposure and see how red you can get out of your pic.

Tracked exposure? Try making and using a scotch mount.

Jerry.

[74tuc]

Try this:

http://www.astunit.com/tonkinsastro/...cts/scotch.htm

Jerry

[Tamtarn]

Thanks for the link Jerry - really interesting the way the Scotch Mount works.

Tomorrow our new scope arrives,we purchased a Skywatcher 8" f5 Newtonian on Eq5 mount with dual motor drives, which we will used to piggy back our camera for wide field shots.

Another learning curve begins

David

[Diamond Rose]

Thanks, David! I appreciate your help.

I've only got a standard tripod. Have fun with your new mount I want one, too lol!

~ Bruce

[Tamtarn]

Bruce it seems that when using a standard camera tripod as I did on this shot, the secret is to use a fast lens and then you can keep the time down.

I picked up the 50mm f2 for $36 on ebay - a bargain.

David

[dugnsuz (Doug)]

Originally Posted by Tamtarn

Thanks Geoff

I have now taken 5 raw images of the same shot with 3 dark frames on the same settings as before. All I need to do now is work out the best way to stack, align and process them.
What program would you suggest for stacking and aligning.

David

Hi David,
Freeware - DeepSkyStacker or Registax4
MoolahWare - ImagesPlus, Registar or manual stacking in PS
Cheers
Doug

[Tamtarn]

Thanks Doug

Might try DeepSkyStacker first and see how I go as I have it already downloaded. Thanks also for the link to Peters Actions on Houghy's thread very interesting also.

David