lunator

Seeing was pretty good tonight. I was looking at Jupiter at x300 Cheers Ian

Very good sketch 🙂. You have captured M36 really well Cheers Ian

This is the WDS info. Only one observation in 2002. 15170-0923RBR 7 2002 2002 1 194 194 2.1 2.1 7.5 16.3 B8V+M2V -096-021 -08 3935 X 151700.41-092258.5 I will have a rummage through GAIA to see if anything fits. Cheers Ian

Hi Mircea RBR7 is listed as a 'dubious double' (note X) in the WDS. This probably means it doesn't exist. I'll have a look through the WDS to see if I can make sense of everything. Cheers Ian

Hi Agnes I think the IAU have a loophole on this one. All planets probably have material in their Lagrange points, and if we compare the relative mass of the planet to the mass of the object Jupiter will be less 'dwarfish' than the others 😁 Cheers Ian

Hi Mircea, Here is a screenshot of 52 Ori. It looks like there are 2 possible visual doubles. They are quite wide. You should be able to look them up on the WDS or Stella Doppie websites cheers Ian

Hi Mircea, one way you can check what you have seen is using the Aladin/Simbad. You can zoom in and out on your target. It might show you the pair you saw. cheers Ian

Welcome back Nick. Looking forward to your observing reports. Cheers Ian

Hi Mircea I have the equation in my book but it is something I have calculated from all my observations over the last 20 years 😁 Cheers Ian

Hi Mircea Interesting result on Rigel 😁. It does fit with the limit of resolution for a telescope. Paul Couteau said to resolve tight doubles you need to working at 2x the aperture so for your 45mm scope x92 fits well. If you combine this with Bruce MacEvoy concept of the resolution ratio where you divide the separation by (116/aperture) to calculate what difference in magnitude will still be visible. I like to substitute magnification for the aperture in the equation as a "how low can you go game" From experience the equation that shows the limits of resolution is 2.5+5(log)((Separation)/(116/magnification) Using this equation 2.5+5(log)(9.42)/(116/92) = 6.87 The Delta M for the pair is 6.5 which is below the limit so it should be resolvable. Cheers Ian

Hi John One of my favourite doubles. It's on the front of my book :). It is closing now. I calculated a minimum orbital period of 600 years but the current estimate is around 1200 years. One curious point is as far as I am aware Herschel never noted this pair. He may have missed it in his observing programme but a 5th star in a well placed constellation would be a target to observe I think. My preference is the pair were too close for Him to resolve around the 1780s. Cheers Ian

I thought I would look at Albireo and Almach in the ST80 tonight. I just used the 25 and 5mm orthoscopic eyepieces. I had started the session with the Moon and Jupiter. The ST gave a very warm hue to Jupiter. I looked at Albireo next at x25 mag. The secondary appeared pale blue (similar to my other scopes but the primary appeared yellow orange rather than yellow that I see in my othe scopes. I moved onto Almach and at x80 magnification the secondary was blue ( I thought I might see a greenish tint.)the primary was again a yellow but had an orange tint as well. Not this proves or disproves anything but certainly the apparent colours in the ST80 are different to the OMC250 and the Newt. Cheers Ian

Hi Olly I have been out tonight with the ST80. Some patchy cloud was moving South at a fairly high speed. I found when I looked directly at the Moon the cloud was clearly moving. When I looked directly between the Moon and Jupiter I could see both of them 'moving' in parallel due North 😁. Cheers Ian

I have experienced the 'migratory Star syndrome' (I've just made that up 😁) . It always occurs then there is a fair amount of cloud around and it is moving at a fairly quick pace but also some decent sized gaps. It does seem to be the brain decides the clouds are either not moving or moving more slowly than they actually are so the star HAS to moving to compensate. The illusion disappears quick if you just stare at the star for a few seconds.

Hi Agnes In my 8" and 10" scopes colour is clearly visible down to mag 9.5 ang then the Purkinje effect becomes noticeable between Mag 10-11 where the fainter star in particular shows a blue tint. Below mag 11 I couldn't see any colour. These observations were predominantly from bortle 5-8 skies. I have moved to a decent bortle 4 sky now so once everything is set up I might revisit some of these pairs to see if that makes a difference. I think it will but probably only 0.5-1 magnitudes. cheers Ian

Hi tico, refractors are excellent double star scopes. Their only real drawback is for tight doubles where you need resolution they tend to get e bit expensive. If we take the Raleigh Criteria and use 5500nm as the wave length of the star then to achieve a clear. Split the equation equals 138/Aperture in mm. So a 120mm scope will cleanly split a 1.15" pair ( assuming roughly equal magnitudes 🙂) Once you get up to 150mm scope or larger refractors get very heavy and expensive. My 200 F6 next will perform pretty well against a refractor and can split pairs down to 0.7" The conditions don't often allow this but when they co-operate it can be great fun to split them. A 120mm refractor could get somewhere close to my newt at the Dawes or sparrow limit but the view show elongation of the pair rather than a clear split. If you want a refractor go for it as you won't be disappointed. If you want to chase very tight doubles you will have to consider a different design. Cheers Ian

Hi Jeremy I'm not totally convinced by this view. From personal experience the most vivid (& false) colours I have seen was in my ST120 but it was more to do with it being an F5 scope. I have seen some nice colours in the 70 & 80mm scopes I have but the best views have been in my 200mm newt with orthoscopic eyepieces. The colours are more realistic the view of Almach, Cor. Caroli or Albireo are stunning. Cheers Ian

I can't help with the SS6 and sketches. I do use SS6 to record observations sometimes. Usually I draw sketches into an artist sketchpad and add notes. I then transfer the information into an Excel spreadsheet. My books are on my bookshelf in chronological order. Cheers Ian

I have the celestron eyepiece and have used it for measuring doubles. The Bob Argyle books says you need a focal length of 2-4m for this to be useable for measurement. I use a 2x Barlow on my scope which gives a focal length of 4.5m (x360 mag). I have measured wider doubles by using the ring micrometer and chronometric methods. Both covered in Bob's book and possible with a phone stopwatch -Ring micrometer method and. Stopwatch/illuminated eyepiece for the chronometric method.

The best 2 periods of clear skies were lockdown 1 and the Iceland volcano back in 2011 (I think 🤔) Aircraft contrails do cause a lot of cloud. More than just the contrails themselves.

It was an enjoyable show although the radio edit on BBC sounds is nearly 1 hour long. For some reason on BBC4 the show is only usually allowed 30mins.

The best view I had of the crab was in a friend's back garden in East Devon. We used their 10" Mak Newt. It was really bright. It looked like a thumbprint with some very obvious detail. A few days later I returned home to London and decided to look at it with my OMC250. I could just about make something out. It really made me understand how Light polluted my skies were and how envious of dark skies I was 😁. Cheers Ian

I saw it Monday in my 15x70s. It was tricky but definitely visible.

Peter, like DaveS I can provide provide some anecdotal evidence. In the early to mid-80's. M31 was clearly visible naked eye. My Garden was in SW London it overlooked Fulwell Golf cours so may have been darker than expected.for the location. Cheers Ian

Great photos, 😁. You have really caught the colours Cheers Ian