Jump to content

sgl_imaging_challenge_2021_annual.thumb.jpg.3fc34f695a81b16210333189a3162ac7.jpg

M51 - My Second Attempt, and my Second Attempt at Drift


CKemu
 Share

Recommended Posts

Ahh the Meade LX90 8", if I ever wanted to give myself a series of challenges, then this scope would be the ideal choice!

I am still learning how exactly to align my scope, but I can honestly say that I am seeing progress, which at this point is spurring me on.

Several Weeks Ago:

ISO 3200 | 5 Minutes (300s) Sub

attachment.php?attachmentid=57272&stc=1&d=1303747436

Last Night:

ISO 3200 | 8 Minutes (480s) Sub

attachment.php?attachmentid=57273&stc=1&d=1303747436

A VERY Forced Stack in DSS:

17 x 480s Lights | 7 x 480s Darks

attachment.php?attachmentid=57274&stc=1&d=1303747436

I have done a few 14 minute exposures to, and noticed the hook streak turns into a "Z" shaped streak, and the galaxy / streaks travel in the same direction. So still a bad alignment issue, that and I think I am now seeing periodic error (the hooks).

My worry is that even with me perfecting alignment, the light pollution, regardless of filter is going to make me loose contrast, and DSS gave me an exceptionally noisy image to work with.

post-22545-133877595429_thumb.jpg

post-22545-133877595434_thumb.jpg

post-22545-133877595439_thumb.jpg

Link to comment
Share on other sites

If you're not guiding, then attempting 8 and 14 minute exposures is ambitious and impressive indeed!

Seriously, though, I wouldn't consider attempting anything over a couple of minutes unless you're autoguiding, even if your polar alignment is good. No-one would attempt exposures of 8 or 14 minutes unguided!

Edited by lukebl
Link to comment
Share on other sites

i would say that the Z shaped stars are due to poor alignment combined with Periodic Error, there will be a certain amount of movement in the optics but that would be more noticable over a longer period....best thing to do is use an off axis guider it wil sort out any flex, mirror flop which is well known in these sort of SCT's and will guide out the PE.....the down side of the OAG is the long focal length gives a narrow field and slower optics of the SCT reduces the amount of suitable guide stars

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.