Yet another M42 - don't forget to clean the dust off your DSLR sensors!

[mrjolly]

My first crack at M42 this year (and my second ever attempt) and it turned into one of those nights!

Started off as a nice clear evening yesterday so got set up & polar aligned (finally getting the hang of it) - and thought I'd start off by doing a few 2 minute exposures to see how well they'd turn out, gradually increase to see what I could push to and then do some short exposures for the core. I'm not guiding at the moment and LP is pretty bad down here so thought it would be interesting to see how far I could push it with no guiding and pretty bad LP.

I managed to capture 5 180s subs when it started to haze over and then small clouds started moving across right where I didn't want them to be so gave up, took a few darks, packed up and came in.

Bearing in mind this is only 5 180s subs & 5 darks and also my first attempt at processing with PixInsight, I'm quite happy with what I've got and managed to do with thanks to Gib007 and Harry's PI tutorials, it's not such a scary program after all.

I'm not so impressed at the huge dust splotches that seem to have found their way onto the DSLR sensor at some point during the last few days that seem to be multiplying!

The moral of the story is, clean your DSLR sensors!

[astrodam]

Very nice image, what type of mount are you running? I get trailing if I try to go over 60secs.

[Pint Of Stellar]

Have you taken any "Flat" subs? I understand these are to help eliminate the problems caused by those pesky dust bunnies.

[LouisJB]

very nice. It's a wide image, what was it taken with, ED80?

[mrjolly]

Hi,

Sorry, forgot to say, taken through an 80ED + field flattener on a HEQ5. I seem to have good and bad days with alignment, sometimes I can get a couple of minutes (and maybe more if I tried it) and other times, even 60seconds shows bad trailing! I've found it handy using Stellarium and PolarFinder to see where Polaris should be and comparing that against the readout I'm getting from the SynScan for getting it roughly in the right place. Still takes me a few minutes to even get Polaris in the polar scope mind...!

I've not taken any flats yet although will probably spend some time at the weekend with an old t-shirt or something and see if I can get anything reasonable enough to use!

[Pete Presland]

thhats a pretty good image! plenty of detail and the running man is clearly visible, obviously some calibration frames will help but nice work so far!

[ollypenrice]

Yes, the real moral of the story is 'take flats' but you will need the camera in just the same orientation for this to work. (There are two ways to do this: mark the camera to scope joint with Tippex or always set the camera aligned to RA and Dec in portrait or landscape. To do this take some several second subs while slewing and see if the star trails are aligned vertically/horizontally.  For repeatability and adding data from different sessions being aligned along RA and Dec is a HUGE bonus in time saving.

Your image has worked well. SOme short subs for the Traezium would be good.

Olly

Edit. By the way, I don't think the dust is on your sensor. On the sensor it gives tiny dark spots just over the pixels that are covered. Your dark spots are well out of focus so I'd suspect a filter or something a little further from the chip.