M82 with just a tri...
 
Share:
Notifications
Clear all

15th Feb 2024: Astro Pixel Processor 2.0.0-beta29 released - macOS native File Chooser, macOS CMD-Q fixed, read-only Fits on network fixed and other bug fixes

7th December 2023:  added payment option Alipay to purchase Astro Pixel Processor from China, Hong Kong, Macau, Taiwan, Korea, Japan and other countries where Alipay is used.

 

M82 with just a tripod and a static dslr

6 Posts
3 Users
4 Likes
2,187 Views
 ah
(@ah_astro)
Main Sequence Star
Joined: 4 years ago
Posts: 24
Topic starter  

I don't know of other people use Pentax's astrotracker function (haven't seen anyone), but it's quite fun.
I made this image of M82 with a static mounted Pentax dslr on a tripod (nothing else). The camera calculates sensor translation and rotation based on build in gps and compass. I use an 'old' manual achromat lens (SMC-A 200/4) fitted with a baader contrast booster.

Seeing was 'so so'. Ursa Minor's dimmest star Eta Umi was just barely visible. Milky way was invisible (bortle scale6/7).

APP processed this stack of 47 lights, ISO 3200, f5.6, with 25 bias', 25 flats, 25 darks. Postprocessing done in affinity photo.

 

m82 RGB session 1 lpc cbg

 

m82 RGB session 1 lpc cbg detail

 


   
ReplyQuote
(@vincent-mod)
Universe Admin
Joined: 7 years ago
Posts: 5707
 

Very interesting, didn't know about that indeed. What is the exposure limit etc, I guess still about 15 seconds per image?


   
ReplyQuote
 ah
(@ah_astro)
Main Sequence Star
Joined: 4 years ago
Posts: 24
Topic starter  

For this example lights were taken with an exposure time of 20 seconds per image. Depending on quality of calibration (gps/compass), focal length and location of the subject, theoretical exposure times can go up to one and a half minute (200mm lens, limited by translation and rotation of the sensor). Practically, I never managed above 50" without ending up with unwanted trails. I am generally happy when I manage 20 or 30" exposure times. Other focal lengths will result in other exposure times.


   
ReplyQuote
(@vincent-mod)
Universe Admin
Joined: 7 years ago
Posts: 5707
 

That's certainly impressive for a non tracked setup, thanks, nice to know.


   
ReplyQuote
(@col)
Neutron Star
Joined: 3 years ago
Posts: 127
 

@ah_astro

Nice. I read about some of these pentax cameras with j built sensor tracking capability I think. Was this one of these models? Nice shot at that focal length


   
ReplyQuote
 ah
(@ah_astro)
Main Sequence Star
Joined: 4 years ago
Posts: 24
Topic starter  

@cwm2col

Thanks. The above image was taken using a Pentax K1, which has the sensor build in. In the past I have also tried the separate O-GPS1 which I think gives similar results when it comes to the tracking itself.


   
ReplyQuote
Share: