Quote:
Originally Posted by xelasnave
I presume you are going unguided? Which is great as in my view it is best to determine the mount behaviour.
Yes, unguided at this stage... trying to get setup, PA & imaging routine set first before exploring the intricacies of guiding. also have a lot to learn about processing
I find my mount likes the balance biased somewhat and not consistent with a perfect balance. Concentrate on RA get that as good as possible and perhaps live with dec problems.
Now that I have some smaller weights, I have good balance in RA... not sure if my mount prefers any bias & not sure how to work that out either... At present my Dec balance is a little out as I am limited by the mounting setup of the Meade 5000. I have tube rings on order which will give me greater flexibility of scope placement & I should be able to get Dec balance spot on too then
Do you have a focuser mask?
Yes, I used Alpha Centaurus for my focus & used a Bhatinov mask
How are you finding CSP?
My Celestron CG5 Adv GT EQ mount has a PA routine in the handset. I think it's called all star alignment, basically it allows you to pick a star & then it off sets, you guide back to centre using handset first, then it offsets again & you use azimuth screws & latitude screw to recentre... I generally do two to three iterations of this. On Monday night I had PA of 4 arc sec in Azimuth & 12 arc sec in Alt. I usually choose a star relatively close to SCP.. in this case I used Alpha Centaurus
I am sincere that your image is something to be happy with as a first attempt..even for later in the game really.
Thankyou, most humbled
I started using short exposures because I could not get the mount to perform somewhat as a compromise but now U am cinvinced one can get better results with short exposures...you are able to drop subs with little remorse...
I'm still working on exposure lengths as well as ISO combinations, hence the mix of 30sec @ 1600 ISO & 60 sec @ 800 ISO. Trying to get least amount of noise & best colour range... basically still experimenting on this. I did try a 90 sec exposure but, to be honest the stars were a bit eggy to decided 60 sec was the limit on Monday
I have stacked huge numbers of subs and I suggest that you limit the number only with reference to what you computer can manage..if it will do 500 and it takes all night to stack that is ok.
My Lagoon was a build up of many subs over various nights with only the best making it but in the end I think I stacked around 300 (maybe more)...my first image was rather ordinary but the last one U was very happy with and frankly U doubr if I could improve upon that last one...that was with the eight and the nikon.
I was limited in the number of exposures I could take mainly because of where Lagoon Nebula was in relation to my mount. Basically I had about 10mm of RA travel remaining before the plastic cover on the Dec part started belting into the plastic cover on the RA part of the mount.... I had been having some issues with my mount on the previous outing on Friday night (which meant I didn't capture any data at all) & had done a factory reset... it dropped out all my movement limits (which I kinda forgot) so, I had to monitor everything carefully to ensure I didn't damage the mount... I probably could have got more subs in but, I'm not the most patient at times. I have some more to learn about the app I am using to control my DSLR; I know I can setup sequences... I just haven't done so yet... this will allow me to walk away & let it do it's thing instead of having to manually initiate every shot. There are some things I need to turn off in my camera too... such as shooting in Raw only, turning off in camera noise reduction, etc... just need time to figure out how to do all that
I suggest the following regularly but I doubt if any take my suggestion seriously but I use a long baffled dew shield to minimise light. I thought of the idea and implemented it before I found Hubble engage in a similar practice. If you look you will see that they extend baffling well past the secondary for what U believe are obvious reasons. The idea is to exclude star light (or street lights☺) from hitting the lens or enterinf the tube..we dont see it but it is there and the sensor picks it up. Mine is about two feet on the 80 mm. I cant provide a photo but it is a sumple cardboard tube with baffles...draw a duagran and mark what light can reach the lens but with and without if you want motivation☺.
Actually Alex, this does make a lot of sense... my dew shield extends probably 6 inches past the objective & I had a dew strap on to minimise dewing... I do suffer in my backyard from neighbours lights & some glow from lights my wife might have on inside the house... Should be simple enough to make though, can you explain the 'baffles' part of it in a little more detail please
Alex
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Quote:
Originally Posted by xelasnave
Also wuth PA I take into account that there may be a slight refractuon due to atmosphere which may vary on the wetness of the sky...So even when pole master says it is perfect and you find there is still a slight drift sky refraction may be the reason...
I need to read up a little more on drift alignment so that once I have done the All Star/Sky or whatever Celestron call their PA alignment process I can look at drift to refine my PA. Other option is to use BYEOS with my DSLR as it incorporates some software for refining PA but, that costs more money so, maybe in time... at the moment I use an app on a tablet called DSLR Controller & I rather like the convenience of not having a laptop out with me
These are my ideas and U can cite no authority so I may be talking thru my hat. .. and of course that could apply to everything that I have said really☺.
There is no substitute for years of experience Alex & I am grateful for your sharing of information & experience with me
Alex
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How is your observatory & caravan setup going?
Cheers
Carlton