Jump to content

Narrowband

First Attempt at the Sirius "Pup"


orion25

Recommended Posts

I recently read an article in Astronomy Magazine about the orbit of Sirius B, "the pup", placing the white dwarf at a good distance from its much brighter companion star for viewing. But, of course, you would need good seeing conditions, reasonable altitude above the horizon (for Sirius, lol), and high magnification with a well-calibrated mid to large aperture scope. I've read about the mystery and myths around Sirius B, notably involving the Dogon people of Mali and ethnographers Marcel Griaule and Germaine Dieterlen as described in Robert K. G. Temple's book The Sirius Mystery. I won't go into the book here, but it had piqued my interest in seeing Sirius B, and finding out that "the pup" was well-placed for viewing (and imaging) for the next few years I decided to give it a go. 

I used my 127mm Orion Mak with an Orion Expanse 6mm EP and a Meade Variable Polarizing filter (to cut glare). At 1540mm focal length my 6mm EP gave me about 256x magnification, a must for trying to see "the pup". Sirius was about 30 degrees above the horizon with good seeing. It was around midnight and a chilly 40 degrees F/4.4 degrees C. I first aimed my scope at Rigel (the distance between Rigel A/B is approximately the same as between Sirius A/B at this time). If I could split Rigel, then Sirius would be a good bet. My scope easily split Rigel so I moved on to Sirius. I didn't use any tracking to allow the image to trail across the field, to make it easier to see "the pup" following Sirius. The variable polarizer allowed me to tone down Sirius' glare and I was able to see a little object trailing the bright star!

Ok. I was able to see Sirius B visually, so imaging should be a breeze, right? Not quite. The extreme brightness of Sirius A made imaging the tiny and much dimmer Sirius B a bit of a challenge. So, after setting up tracking and attaching my Nikon DSLR to the scope, I tried several different exposures from 1/8 sec to 30 seconds at ISO1600. I snapped only about 40 exposures because I didn't plan on stacking them; this was just an experiment. At some point, I'll try the planetary imaging approach with one of my space cams but on this particular night I just wanted to see if I what I could get with a DSLR.

After uploading the images to computer and tweaking them in Photoshop I was pleasantly surprised to find a few of my 1 second exposures captured "the pup". I scrutinized them carefully to make sure I wasn't seeing artifacts or glare, and compared them to images taken by others. 

So, after all of this narrative, here are images of Sirius A/B (cropped) and a prime focus shot of Sirius:

1217187852_ASTRONOMY-SIRIUSAB12-06-19CAPTIONSSM.thumb.jpg.1e16030c06c398e161622e5df3355fa7.jpg

2045877546_ASTRONOMY-SIRIUS(PRIMEFOCUS)12-06-19SM.thumb.jpg.963dd38b3d0fa072a613c10178fb5a5e.jpg

Cheers!

Reggie :) 

  • Like 12
Link to comment
Share on other sites

Ah brilliant!  I can see the little blighter.  Thanks for posting Reggie, that was a very interesting read.  If you are planning a plantary approach I wonder if an IR pass filter might help settle the seeing issues a little.

  • Like 1
  • Thanks 1
Link to comment
Share on other sites

3 hours ago, MartinB said:

Ah brilliant!  I can see the little blighter.  Thanks for posting Reggie, that was a very interesting read.  If you are planning a plantary approach I wonder if an IR pass filter might help settle the seeing issues a little.

Thanks, Martin! An IR pass filter is a great idea. I'll try that with my planetary camera ;)

Link to comment
Share on other sites

Thanks for posting, the ideas of observing without tracking and a polarising filter are clever.

I've never tried for the pup as Sirius mostly looks like a wobbly disco ball from where I live!

  • Thanks 1
Link to comment
Share on other sites

I had found a blog with tips for observing the pup, https://florin.myip.org/blog/how-see-sirius-b, and the author suggested the trailing method to make sure you were actually seeing it follow Sirius A. I had used a polarizing filter on Venus to see the phase more easily and also the image some features.   A light bulb went off to try it on Sirius A since it's sooo much brighter than its companion and I found it to work pretty well :) .

Edited by orion25
add link
  • Like 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.