Upgading my telescope

[Chris]

I think I've confuesed you a bit, I'm not the best at explaining things:D I don't have a 150p dob, its a 150p scope attached to a HEQ5 equatorial mount that is motor driven to compensate for the Earths rotation. Its not so much the scope picking up the detail as its the mount tracking the sky accurately enough to allow the DSLR camera to collect the photons without smearing the photons across the camera sensor, you want to track the sky accurately enough that the stars remain pinpoint during a long sub exposures, a number of these sub exposures can then be stacked. The three main components are mount, camera, and scope possibly in that order of importance. Your 130p can be stuck on an equatorial mount to track the sky the same as my 150p can, the only thing I would want to check is can you achieve focus with a DSLR camera on the 130p? sometimes there isn't enough back focus on some reflectors, I found this out with my old blue tube 200p which I couldn't achieve focus with. If you ask on this forum if the 130p can achieve focus or not with a DSLR camera then if the answer is yes I would recommend to anyone who had a 130p wanting to get into DSO imaging to get an eqautorial mount to stick it on, then get an RA motor drive, plus cheap Canon DSLR, and a t-ring to attach the camera to the scope. The stacking of these sub exposures is done in Deep Sky Stacker (or similar) this is free to download and like you say stacks the images ontop of each other to increase the signal and reduce the camera noise thus eventually giving a better picture because theres more data, you can't take one massive long exposure for two main reasons, one is that no mount could track accuralety enough to collect say 5 hours of data in one shot and secondly if you did manage this you would massively oversaturate the brighter parts of the object you want to image. like you say you don't have to have the galaxy exactly in the same place on each exposure but each exposure e.g. 60 seconds needs to have round stars from accurate tracking so that each sub exposure isn't smeared, so you need to track accurately for this amount time, I started out taking shots of only 20 seconds and stacking these to get ok results to begin with, then as you get more expierence with polar alligning etc and better kit each the subs exposures get longer and the detail you capture gets better. The final processing in say Photoshop isn't adding anything that isn't allready there, all the data your playing with is the data you've captured but some of it isn't very visible to us yet, remember that the camera sensor isn't the same as the eye, a basic processing expample would be adjusting the levels to make darker shades that are captured but not very visible us brighter so we can see them, we definatley don't draw ontop of the images, only play with the data we have captured.

[Charlie_132]

oh i think i understand now, so the mount you have keeps say m81 in focus and it wont move, your camera takes in a lot more light then the human eye, and then you stack the photos on top of each other that youve taken, and then you do a few finishing touches using photoshop or something ? what finishing touches are they ?

ive uploaded a few mre photos to my gallery (2 of jupiter and 1 of the moon)

i worked out that if i waited til jupiter had gone out of sight but kept a track of it through the 25mm eyepiece, then switched to a 2x barlow and a 10mm lens, i could see the detail on jupiter a lot clearer and capture it on my mobile (the green filter was no use during the daylight, im going to try it in darkness tonight at 1am which is when im guessing it should be used