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Finally got out last night


JOC
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So after months of frustration I decided to put a big effort in and use the telescope last night - I dumped it all outside about 8pm to cool down, decided to run the mains power to the GoTo and got all my chairs and tables out ready with the EP boxes.  About 21:30  I went outside with Stellarium on the phone and found Jupiter already up so thought I'd see what could be done.  I've got one of these fancy SW WiFi things (Crimble pressie), but thus far I hadn't had huge success with it - anyhow with time on my side I gave it another try.  I turned the telescope compass North - I;m close enough to celestial north here to make that possible, and used the mobile WiFi app. for the calibration - it gave me the option of Jupiter for first callibration object (which I took  as I could clearly see it) and then suggested Vega - I wasn't so sure that this was up, but thought that maybe if I told it things were OK I'd end up with something useable.  As it happened it seemed to work out OK and it then 'drove' to a number of objects successfully and some unsuccessfully.  

I had a good look at Jupiter - two nice bands and fair amount of darkness and indistinctiveness going on at pole I was viewing at the top.  3 little moons neatly circling - took quite some time looking - the XW 5mm wasn't good - backed it off and after several changes settled on 12mm (x100) which made it a reasonable size and clarity.  Stelalrium said there were some Messiers above and a bit to the left and the right, of jupiter but I could not see these - I think they were about mag 6-7 so maybe it wasn't dark enough.  I still seem to have some issues with the automation driving the scope in the vertical alignment - horizontal is fine, but when I can't find an object I never know if I am correct on the vertical axis.  So I reasoned in the finish that with a not very dark evening and a huge moon up (though nicely hidden behind my house just about then) maybe FGF's (that's faint grey fuzzies) weren't the best type of target.  So what next?

The wifi app on the phone has a database so I started flicking and spotted double stars!  These had far more potential - points of light!  Knowing the horizontal was OK even if it missed them vertically all I'd need to do was shift the telescope vertically until something plausible came into view and then see if it was a double.  

So I started with Alberio - actually it landed plumb on it - my eye's don't seem good enough to see the two colours in focus, but defocussing pulls out two beautifully distinctly coloured circular rings - one gold and one blue.  

Where next?  I need to start to get my eye in on what the degrees mean for me in terms of where I can see - several I tried were behind trees - then I found one the app. called Epsilon Boo?  This was trickier than Alberio - the secondary seemed much fainter, but I still got a clear split.

I didn't have any luck with the Hercules great cluster (whatever that was) the app. reckoned it was out of the range of the telescope!

The Goto suggested Zeta Lyr - this the system found and this split nicely, then I thought Lyr.....that's where the double double is - memory failed - which was it?   The Goto said we could find Epsilon Lyr so off we went - the moment we arrived I knew I had found the double double and I hadn't managed to split them the last time I visited - at about 14mm it was still together - still I had recently collimated the scope - probably first time out since doing and as I reported in other thread I reasoned High mag shouldn't hurt points of light so I went staight for the Pentax 5mm (x240) - straight away four distinct little stars popped into view all clearly separated - well chuffed and I spent some time admiring them.  By then my daughter had arrived home and I knocked it on the head around 23:15 so not long, but with the issue of the vertical goto movement being non-trustworthy I thought I had probably had enough - and it was getting rather cold!

So the takeaways were:  Chuffed with the double double, don't trust the vertical goto - need to find out why, the fancy Pentax is brilliant for doubles, the scope needs to be well collimated for doubles, Jupiter is always worth a look, and I need to develop a rule of thumb as to what degrees are in my lines of sight.

 

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Brilliant Vega is high up under is Altair and over to the left half way down the sky is Deneb this is known as the summer triangle.

The Hercules cluster is a globular cluster of stars very nice in a scope Messier 92 is in Hercules as well that is a nice globular cluster.

if you can view South check out Saturn later on 12.30ish that will blow you away.

Edited by wookie1965
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Nice session @JOC, great to have things working nicely, and good to hear the collimation is now sorted.

Epsilon Boo, that’s also known as Izar and is one of my favourites. Unequal brightness stars and quite a tight split make it a bit of a challenge but always satisfying to get the split, the colour contrast is nice too.

What makes you say you don’t trust the alt axis on your mount? Does it have some play in it? The goto seemed to be working ok though?

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2 hours ago, Stu said:

Epsilon Boo, that’s also known as Izar and is one of my favourites. Unequal brightness stars and quite a tight split make it a bit of a challenge but always satisfying to get the split, the colour contrast is nice too.

What makes you say you don’t trust the alt axis on your mount? Does it have some play in it? The goto seemed to be working ok though?

It is always great to have something confirmed - in this case the unequal brightness - when I find something for the first time I am sometimes not sure if I see what I am meant to see (if that kind of makes sense!).  So when I am able to report something that is then confirmed I feel extra chuffed to have made what appears to be a 'correct' observation so many thanks for that.  Yes, the split was quite 'tight' and it was interesting to split a pair that had uneven brightness - it gave me a much better idea of some of the differences to bear in mind when I go and look for 'doubles'.  IIRC it was again the Pentax 5mm which locked in on them - it seemed very good for double stars, I've tried it on FGF's and it is not the best for some of them - it seems to not make them bright enough, but it seems to be 'the business' for double stars. 

It's a Goto Dobsonian mount and its always seemed very sensitive to the vertical balance of the scope.  I have received instructions relating to removing bits of the mount and doing some tightening (I'm very reticent to do this in case I irreversibly bust it), and/or maybe adding some weight to the opposite end.  Last night I tried it without it's home-made light shroud when adds weight, but it still sometimes needs a shove to get it driving up or down - I think even BIG EP's like the Pentax seem to alter the balance, but I don't always remember to remove then before letting the Goto kick in.  Hence it is making FGF's rather difficult to know whether it has really found them or just ground to a halt.  For example, I asked it to recentre Jupiter several times and it would get the horizonatl turn correct, but I would need to swing the scope vertically to find Jupiter in the EP.  Now it is not a problem to do that for Jupiter or a clear double star, but finding FGF's is rather more problematical.

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That’s great! As you build more experience you will learn to trust what you are seeing. That will become helpful so you know if you are looking at the right object or not.

I understand now what you are saying regarding the vertical axis. I believe the Skywatcher Goto dobs have encoders built in, so even if it stops and you have to give it a shove, it should still find the correct object.... I think!

Others will be able to directly assist maybe, but definitely changing from a heavy to a light eyepiece will change the balance. There are a number of solutions you could try. Assuming it is top heavy, you can find a way of weighting the base. Attaching a magnetic knife rack to the base can allow you to attach steel weights that you can slide up and down as needed to balance the scope. If I can find an example I will post it up.

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Sounds like you had a good night :)

The great cluster in Hercules should have been visible to you, and can be seen with a 200p dob with stock eyepieces. I think the app was lying when it said it wasn't visible to you. At this time of year it's almost overhead at 11pm, so should also be in the clearest part of the sky. Hercules constellation doesn't have a shape that easily sticks in the mind like Orion, so to find it manually look for Cygnus (the main stars form a kite shape) and draw an imaginary line from Deneb, the brightest star in Cygnus, through the brighter star of Vega for a further distance approximately equal to the distance between Deneb and Vega. The main square of Hercules sits just above that line, and M13 itself lays just outside the lines of that square. It's not a faint grey fuzzy but a blob of stars and is still visible without astro darkness

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