LX90 for astro photography

[poltabs]

I was wondering what the limit of exposure times are using an LX90 without a wedge? Would it be possible to do up 2 mins? Or is it more like a realistic 30 seconds?

Anyone with experience?

Thanks

Kevin

[poltabs]

I should also ask is the mount on the LX90 accurate enough for astro photography or is it generally too lower quality for that kind of work?

Cheers

Kevin

[Paxo]

Hi Kevin,

The problem that you have with the alt/az mount is one of rotation. Even if your mount can keep your intended target spot-on centre you are going to get some degree of rotation. I have seen successful images on this site taken with alt/az mounts so it is most definately possible. The amount of rotation you will get is very dependant on where in the sky you are looking, but I guess you will be looking at the 30 second end of the spectrum and not the two minutes, just take lots of short subs and let the stacking software take care of the rotational element for you - a very good work around. I have seen tables on the net for calculating the time of exposure possible using SLR/lens combination, I'm sure they must exist for telescopes too.

Sorry not to be more precise, but be positive, you should be able to carry out some degree of astrophotography with that set-up.

Steve..

[steppenwolf]

Wot Steve (Paxo) just said - nothing to add!

[barkis]

Nothing wrong with 30 second exposure stacked is there? I have seen some good results via this method using a DSI and the software provided with it.

A Wedge is a more suitable setup, but you can get resuts Alt Az.

Join the Meade 4M forum, lots of help and advice there, and images via that route.

Using a focal reducer will allow increased exposure times. Imaging at f10 + is planetary and lunar stuff. You can come down to f5 for DSO's

Ron.

[dph1nm]

This is an excellent link for working out the maximum time you can exposure for without noticeable rotation on an alt-az mount:

http://www.skyinsight.com/wiki/index.php/What_is_the_Maximum_Exposure_in_Alt/Az%3F

NigelM

[CELESCOPE]

I imaged for a few years with the Alt AZ set up .having a gps 8 Celestron. i did have the advantage of using it with the fast star system , getting the f ration down as low as you can get will allow more exposure time time. mine was f1.95. a rapid f ratio. i mainly imaged in the east at around 80 degrees, also i used maxim which does have afix for rotation, , the longest i have gone is 90 seconds, but on the whole 1 min was all i needed,

The camera i used was an Atik 2hs , which no longer is produced , but camera,s off similar type are still available .

All is not lost with ALT-AZ

I have proved it so ,

Rog

[ribuck]

Would like to just point out that if you use a meade Dsi Pro II and above, it uses Nasa's Drizzle technology. this is essentially some fancy software which processes your image and somehow applys some field de-roatation algorythm to compensate for it in the final image.

i know this is going to be limited, but they are decent entry level ccd's with some good features. So might be worth looking into.