135mm Carina Nebula Ha

[Mickoid]

I took out the modded Canon 550d with a Pentax 135mm f 3.5 attached last night and shot some data using a 2 inch 7nm Ha filter. I mounted it on an iOptron Sky Tracker pro and I must have nailed the PA pretty close because I managed 3 min subs with it. I actually shot these at 3200 iso in JPG Monochrome format, 15 subs which gave me 45 mins worth. The tracking was so good it unfortunately created walking noise which I was able to slightly reduce by trashing the Blue and Red channels and saving the Green channel as a Grayscale image.

The combined age of the camera and lens I used is over 55 yrs but I reckon this Pentax lens still holds up well and it's one of my favourites for Widefield.

[pkinchington]

Hi Mick,
What I like about using camera lenses for astrophotography is that once you set the lens on infinity and perhaps stop down a stop or two - you don't have to worry about resetting focus. Is your Pentax lens an old manual focus?
Cheers Kanga

[Dave882]

Nice pic Michael! I actually really like Carina in Ha and you’ve done a great job!

[Mickoid]

Yes, everything is manual, especially with the K-mount to EF-mount adapter.


Thanks Dave, it takes a bit of exposure to get a reasonable signal to the sensor with the 7nm Ha filter and a OSC camera. Focus can be tricky as well but it's worth it in the end.