Someone asked a question about what a 5-minute exposure looks like from Slooh.com – specifically what kind of results can be expected from a 5-minute mission?

Background

Slooh.com provides its members with reservation slots, or missions, that are 5 minutes long on most telescopes, and 10 minutes long on the Slooh.com Canary One telescope. Given that most imagers take exposures that are much longer than 5 minutes, what are the results you can typically expect from the Slooh.com telescope since the integration time is so short?

Bear in mind that the Slooh.com telescopes are quite high-end: Canary One is a PlaneWave CDK20 with an aperture of 508mm, a list price of $35,000 and weighing in at 140 pounds; and Canary Two is a PlaneWave CDK 17 with an aperture of 432mm, a list price of $24,000 and weighing in at 106 pounds. So the telescopes have a lot of light-gathering capability and they have cooled CCD cameras attached to them as well. The result is relatively short integration times with great results.

Given the capabilities of these telescopes, Slooh.com members commonly image objects as faint as magnitude 20.

Sample Image – Mag 10.5

This is a sample image of NGC 1535 taken using a 5-minute mission:

NGC 1535 has an apparent magnitude of 10.5 and this is a great result since there’s a lot of detail visible in the nebula and the central star is clearly visible.

The actual exposure time based on the processing preset used and details from the FITS header is as follows:

  • Luminance: 50 sec
  • Red: 20 sec
  • Green: 20 sec
  • Blue: 20 sec

The telescope produced four FITS files: one for each color filter:

Minimal processing was done on this image: in MaxIM DL the files were stacked and a DDP stretch was applied to the image. In Photoshop, the image was stretched slightly to make the background darker and the image was cropped and resized.

Sample Image – Mag 16.7

This sample image is of the Twin Quasar SBS 0957+561, at magnitude 16.7 having a distance of 8.7 billion light years:

The image clearly shows the lensed quasar with excellent details and this was done using a single 5-minute mission (the actual exposure time was the same as the preceding example).

This image was taken in excellent conditions using the Canary 4 Solar System telescope (355mm aperture). Fortunately, excellent seeing conditions are not difficult to come by at Slooh.com because the telescopes are located at a great observing site.

Conclusion

In this article, I demonstrated what a typical 5-minute exposure on a Slooh.com telescope produces. I also demonstrated what a faint object looks like through the Slooh.com telescopes. You also learned about the actual exposure time used for the reservation.