Double stars

[leo82]

Hi all,

How clear was it last night!

I decided I would start concentrating  on double stars more now and feel I got off to a good start.

First off for each target I used my heritage 130 with supplied 25mm, 10mm and a celestron x2 Barlow. I started each target with the 25mm, then changing to the 10mm and finishing off with the 10mm and Barlow.

First target was mizar. Through the 25mm I could see mizar and alcor making a triangle with a smaller fainter star, changing magnification I could split mizar a and b, albeit a diffraction spike running through the companion!

Next target was alberio, wow this is my favourite object(s) in the sky to date. View was amazing through all eyepiece variations, easy split too for such a nice object(s). Primary star looking a nice orange/gold colour and its companion star a lovely blue/white colour.

 I then moved to almaak, I managed to split it easy enough but after seeing albireo it looked a bit dull. Still interesting to find and then spend time splitting.

Polaris was the next star, it looked nice and bright but that kind of hindered my chances of seeing the faint companion next to it, on my list for high magnification when I get a bigger telescope.

The last star was the double double in Lyra. Easy to locate next to vega with the 2 primary stars already split in the 25mm eyepiece, couldn’t split them down to four stars though, more magnification I think with these too. 

 

[MarsG76]

Albeiro seems to be everyones favourite double star.. and believe it or not, I haven't ever seen it.... ever in all those years gone by.

 

[leo82]

Find it next your out, you’ll be glad you did. 

[Stu]

Very nice report, and some favourite objects observed.

I have been observing similar targets with my Heritage 130p so should be able to give a valid comparison. With a 5mm BGO i.e. x130 mag, I was able to split the Double Double, and also see the tiny secondary to Polaris. So, this is the same as your high power (10mm plus Barlow)

There are two possible answers I think. First is collimation. Are you sure this is spot on? I don't really get strong diffraction spikes in my scope so perhaps your collimation is off and you are putting it down as a diffraction spike?

The second difference is obviously the eyepieces used. The BGO is very sharp, ideal for this sort of observing so perhaps  if your barlow or the standard eyepieces are not great  then this could be hindering your success.

Check your collimation first I would say and see how you get on.

[leo82]

To be honest it’s probably collimation, I just can’t get my head around it, even though I’ve got a Cheshire and lazer collimator and they indicate it’s collimated.

 

[Stu]

1 minute ago, leo82 said:

To be honest it’s probably collimation, I just can’t get my head around it, even though I’ve got a Cheshire and lazer collimator and they indicate it’s collimated.

 

Have you done a star test? I assume the secondary has limited (or no?) adjustment so just tweaked the primary on mine. Defocus a modestly bright star (Polaris is go because it doesn't move much!) and make sure the rings are concentric. Make sure the star is re centred after each adjustment, and check at higher powers then bring the star back to focus to check it is bang on. Mine is not perfect but close enough for now.

I also made a shroud for the scope to keep stray light out, but I also found that my breathing was affecting the view quite a lot by inducing warm air currents which are very noticeable on a defocused star. The shroud stops this happening too.

[domstar]

A good read. I always find Mizar quite tricky but Polaris without problems. My favourites at the moment are Iota Cass and Al Salib in Delphinus. Your report makes me want to get out there again.

[leo82]

1 hour ago, Stu said:

Have you done a star test? I assume the secondary has limited (or no?) adjustment so just tweaked the primary on mine. Defocus a modestly bright star (Polaris is go because it doesn't move much!) and make sure the rings are concentric. Make sure the star is re centred after each adjustment, and check at higher powers then bring the star back to focus to check it is bang on. Mine is not perfect but close enough for now.

I also made a shroud for the scope to keep stray light out, but I also found that my breathing was affecting the view quite a lot by inducing warm air currents which are very noticeable on a defocused star. The shroud stops this happening too.

I have never done the star test before so I will try this and hopefully it will be better. Thanks. What did you make your shroud out of? Did you do an exterior wrap over the truss or underneath?

28 minutes ago, domstar said:

A good read. I always find Mizar quite tricky but Polaris without problems. My favourites at the moment are Iota Cass and Al Salib in Delphinus. Your report makes me want to get out there again.

You should definitely get out there again. I can’t wait to search out more of these hidden treasures!

[Stu]

45 minutes ago, leo82 said:

What did you make your shroud out of? Did you do an exterior wrap over the truss or underneath?

See this thread for my Blue Peter Solution. Sure it is possible to do better, this was quite a quick job (as many of my 'projects' are!). Works well though, just made out of thin (2mm) hobby foam.

 

[Stu]

1 hour ago, domstar said:

A good read. I always find Mizar quite tricky but Polaris without problems. My favourites at the moment are Iota Cass and Al Salib in Delphinus. Your report makes me want to get out there again.

It is strange how different objects are challenging to different people. I've always found Mizar very easy. It was the first object I ever observed and it splits nicely even in a small 60mm frac and my 65mm Newt. I've even just about done it with 15x50is binos!

Polaris, and other similar pairs with very unequal brightness can be a challenge as the glare from the primary can wash out the tiny secondary. Rigel is another nice one along these lines. I guess they are a good test of both collimation and scatter control in the optics.

[Special K]

Great results @leo82!  It really was an incredible night out last night and around midnight the wind was calming down a lot......enough for me to make a split at 1.9" of a tiny little binary Struve in Camelopardalis.......I'm so sorry, I don't have my books so cannot tell which one it was.

What I did see which may interest you was a visual double called Webb 2 to the east of Pazmino's cluster.  This has a lovely color contrast similar to Albireo, though not near as bright.