Testing out the Dob - mostly inclined towards clusters

[Ratlet]

I put the dob out to cool earlier in the evening and decided to get familiar with the Dob.  Previously I’d only used the 130PDS on an Alt/Az mount and for me the Dob was a bit different.  I setup with a cheap sun chair to try and get to a reasonable height.  It didn’t work well, but it did work.  Sitting is a far more civilised way of observing, even if you are mostly sitting on the arm of the chair!

M42 is rapidly heading into the out season so I kicked off with that.  It’s far from the hardest thing to find so I kicked off with the 16mm OVL Nirvana for 78x.  I looked at it the other night with the same eyepiece and was blown away by how clear the Trapezium looked with it and again tonight.  With a fairly short amount of time observing (and the neighbours kitchen light on) the amount of detail was brilliant.  Previously I would describe the nebulosity as like a swift and this was still obvious however now the inside of the ‘wings’ were filled in with faint nebulosity. 

I attempted M31 but it was very low down and was quite disappointing only the core region was readily visible.

I figured Mars was worth a punt but I don’t think my eyes or the scopes collimation was up for it.  It was orange.

Since I was in the neighbourhood, I decided to test out the inclinometer.  M1 was just below mars so I got to the correct altitude and panned east.  To my surprise the nebulas wandered into view reasonably central.  Largely lozenge shaped the nebulosity was obvious.  I wasn’t really expecting that to work so well.  Using the inclinometer became a running theme…

I really enjoyed the clusters in Auriga in the 5” so decided to try them next.  I used the digital inclinometer for this and dialled in the correct altitude and then just panned west to east in the rough area.  Initially I landed on M38 with the included Stellalyra 30mm Superview (42x).  The cluster was very dense with the larger east side being separated by what looked like a dark lane from the less starry west side.  There was also obvious fuzzyness to the South East which I think might have been NGC 1907.

Once I figured out where I was I hit M36 next.  Smaller but still dense I didn’t really stay long as M37 was up next and it’s probably one of my favourite clusters.  With the 30mm it’s lovely, like a cluster of cluster with bright stars mingles with graininess of almost resolved stars.  Stepping up to the 16mm showed more stars and more graininess.  I suspect this cluster would just suck up magnification and keep offering more.

After a quick break I decided to head over to the East and attempted to see the Rosette.  I could see the cluster easily enough, but I’m never sure if I can see the nebulosity.  I did see the Christmas tree cluster.  I see the shape clearly.  The brightest star marks the pot of the tree?

The Esikimo Nebula was a bit more of a challenge to track down and I had to resort to star hopping over from Wasat.  With the 12mm BST (104x) and UHC filter it was very bright.  I couldn’t see any real detail but what a difference from the 5”.  I previously described it as a good target to train your averted vision.  With the Dob it was just there all the time.

Wrapped up with the Beehive cluster which was cracking with the 30mm.  It just about takes it all in.  First time I’ve noticed that some of the stars have different colour in this cluster.  There is a definite orange bias to some of them (although to me it often feels like describing colour of stars is more like describing the colour of white LED lights being orange or blue).  I dropped down to M67.  This is another really nice cluster and I highly recommend having a look at it.  Surprisingly dense.  I felt it looked better at low power than high.

I did try a few more targets in Leo and Ursa Major, however there were high clouds rolling in and I couldn’t find anything.

In all I’m delighted with the Dob.  I think it will really come into it’s own with a proper observing chair (just as soon as RVO get stock).  For finding large objects like clusters having the inclinometer is like having cheat modes on and every time I tried it I wound up getting the target in the FOV of the 30mm.  An Azimuth setting circle is the next upgrade.  The AZ5 will be getting one as well.  To avoid blowing my retinas I covered the screen of the inclinometer and an old mobile with red acetate from ebay.  This dimmed it down nicely and helped preserve my dark vision (a bit of a wasted effort as the neighbour’s kitchen light was on the whole time).

I bought a sack truck with a long toe plate for moving the dob and it’s basically made it grab and go as it just needs to get from the shed to the garden.

No complaints about the Dob.  It works as intended.  Apart from the collimation which was my own fault as I didn’t check it at the start of the evening.  It’s a nice compliment to the 5” Newt and I’m glad I went down this route (I was thinking about getting a refractor). 

I did plan to do some sketching but a combination of excitement and intimidation from the clusters (too many stars!) meant I settled for being greedy instead.

 

[Spile]

I am with you regarding the clusters. One thing I really enjoy looking at with my Dob are double stars. They are a great alternative when skies aren’t so dark.

[Captain Scarlet]

Very nice read. What size is your dob? It may well be in your sig but I don’t know how to see a sig on my phone.

M37 is a favourite of mine. I always look out for the prominent bright red star in a darker patch right at the cluster centre, a lovely sight.

Cheers, Magnus

Edited March 11, 2023 by Captain Scarlet
37 not 47!

[Ratlet]

39 minutes ago, Captain Scarlet said:

Very nice read. What size is your dob? It may well be in your sig but I don’t know how to see a sig on my phone.

M37 is a favourite of mine. I always look out for the prominent bright red star in a darker patch right at the cluster centre, a lovely sight.

Cheers, Magnus

I just got the 10" Stellalyra.  I've also got a 5" 130pds.  At some point I need to get them both out and do a comparison.  The only object that had a definite "that's different" moment was the Eskimo nebula.

Delighted with it though.  Very pleasant to observe with.

Edit:. Missed the red star in the middle of m37!  I didn't see that.  That's what I get for not sketching I guess and being in too much of a hurry 

Edited March 11, 2023 by Ratlet

[Kon]

Nice report and first light (?). You may want to consider a good quality OIII for the fainter nebulas (I am not sure what your skies are). 

[Ratlet]

13 minutes ago, Kon said:

Nice report and first light (?). You may want to consider a good quality OIII for the fainter nebulas (I am not sure what your skies are). 

Bortle 4/5.  I'll have a look into it the Oiii filter. At the moment I'm enjoying working with the UHC and trying to figure out how it always seems to have a thumb print on it.

Second light, but first time using it for DSO which was it's intended targets.  Had it out on Wednesday to catch Jupiter and Venus.  Jupiter was pretty decent considering I was literally viewing it through branches.

Edited March 11, 2023 by Ratlet
First light.

[Epick Crom]

Hi Ratlet, nice first light report on your new 10 inch dob!

My scope is the same size as yours and I love the views through it. It will serve you well for years to come.

 

Clear skies

Joe

[Littleguy80]

13 hours ago, Captain Scarlet said:

Very nice read. What size is your dob? It may well be in your sig but I don’t know how to see an sig on my phone.

Try viewing in landscape mode on your phone. I stumbled across this recently and found signatures appear that way

[Captain Scarlet]

2 hours ago, Littleguy80 said:

Try viewing in landscape mode on your phone. I stumbled across this recently and found signatures appear that way

And so they do! Thank you for that.

Magnus

[Mr Spock]

Nice report. There are so many targets for a decent size Dob. I'm sure you are in for many more fine sessions.

[Guest]

Ten inch dobs are great for looking at just about anything.   Make sure to have a OIII filter handy at some point.  Sometimes they do a better job then a regular UHC filter. 

[Alan White]

Nice report and pleased you have found the Dob a sucess.

On the ebing seated, well that is a wonderful observing treat whatever you look through.
The real issue is finding a suitable perche.

Observing Chair?
Stool?
Armchair?

A wide choice and one that might keep you obsessing for some time to come.

 

[Mr Spock]

The only complaint I have with my Dob is the eyepiece position. When the scope is pointing straight up you need to be a gymnast to climb over the base and get to it. I don't know why they don't put them on the side 

[Ratlet]

31 minutes ago, Mr Spock said:

The only complaint I have with my Dob is the eyepiece position. When the scope is pointing straight up you need to be a gymnast to climb over the base and get to it. I don't know why they don't put them on the side 

I'll watch out for that.  My base is currently extra wide as I need to put a base board down to stop it sinking into the grass.  A side from an old kitchen unit was hand picked for its availability.

I've not tended to observe near zenith as I find it hard to navigate with the alt az.

2 hours ago, Alan White said:

Nice report and pleased you have found the Dob a sucess.

On the ebing seated, well that is a wonderful observing treat whatever you look through.
The real issue is finding a suitable perche.

Observing Chair?
Stool?
Armchair?

A wide choice and one that might keep you obsessing for some time to come.

 

Going to get the geoptik Nadira.  Just waiting for rvo to let me know when they're in stock.  The mother in law does upholstery so I'm hoping I can get her to do a seat cover.

Edited March 12, 2023 by Ratlet

[PatG]

A great first & second light reports Ratlet, got yourself a bargain there.
 

I recently acquired a second hand 10” dob (OOVX10L) and have enjoyed a couple of tantalising sessions. I am enjoying the simplicity of it and it’s nice to navigate to the target manually for a change. I’ve also got a digital inclinometer but not fitted it / tried it out yet. I’m interested how you are going to approach the Azimuth setting circle, Im deliberating over that at the moment. Clear skies! 

[Ratlet]

Just now, PatG said:

A great first & second light reports Ratlet, got yourself a bargain there.
 

I recently acquired a second hand 10” dob (OOVX10L) and have enjoyed a couple of tantalising sessions. I am enjoying the simplicity of it and it’s nice to navigate to the target manually for a change. I’ve also got a digital inclinometer but not fitted it / tried it out yet. I’m interested how you are going to approach the Azimuth setting circle, Im deliberating over that at the moment. Clear skies! 

I'm going to get the local printers to do a print of a setting circle.  I'll make it on here ( https://www.blocklayer.com/protractor-printeng ).

After that it'll just be doing this https://youtu.be/ufExHsPD4lg

[Ratlet]

As an interim solution to the azimuth circle I had a light bulb moment:

The knob you tighten to control the azimuth doesn't move when you rotate the tube, and neither does the washer below because of a needle bearing.

Quickly printed up and A4 sized setting circle, laminated it and popped a hole in the middle.  It's a bit small but doesn't move as you rotate the dob.  Should do for some initial testing.

I think for a marker it might be nice to get decimal accuracy on the degrees.  I know that's broadly how slid rulers worked in a way but will need to read up on it.  Will be a couple weeks I think till I can test it out as back to work tomorrow.

[Mr H in Yorkshire]

How are you to read the azimuth angle, an arm with pointer, attached to the stationary base? If I understand correctly, if you do that you'll need to align the ground base to North. To get decimal accuracy you'll need decimal degree initial alignment. Am I just a pain?

Edit. Thinking about this, does the dob base have a flat outer edge? If so you could determine the circumference and mark/print a strip with the degrees marked off, probably enough resolution to mark part degrees if not actual decimal parts. I have no doubt this is not an original idea. Attach the pointer to the ground base.

Edited March 13, 2023 by Mr H in Yorkshire

[Ratlet]

1 minute ago, Mr H in Yorkshire said:

How are you to read the azimuth angle, an arm with pointer, attached to the stationary base? If I understand correctly, if you do that you'll need to align the ground base to North. To get decimal accuracy you'll need decimal degree initial alignment. Am I just a pain?

Not all a pain!  I'm however prone to overthink things and having someone like yourself around helps to stop me flying off.

The setting circle is fixed to the bottom base via the tension screw.  It doesn't rotate as the dob does.  I'll probably use some magnetic strip to hold a bent bit of metal as a marker.  It'll stick to the dob base and rotate around the setting circle.

I think you are right, I'll need to align the setting circle north, but for fine alignment I can just move the marker, so long as the setting circle is north ish.

For decimal accuracy I will need decimal alignment which might not be possible.  I've also just realised what I was thinking of to get that is a Vernier scale on the marker.

[Mr H in Yorkshire]

Good solutions, I like magnets and yes, a vernier is the item you need, but do you really need 1/10ths? In practice a half degree mark would probably do and you could 'eyeball' it for smaller amounts, it's surprising how accurately one can estimate visually - you'll need a light too don't forget.

[Sunshine]

On 10/03/2023 at 19:21, Ratlet said:

It was orange.

This basically sums up what Mars looks like at the moment except maybe on a night of exceptional seeing, nice report.

Edited March 13, 2023 by Sunshine

[Ratlet]

46 minutes ago, Mr H in Yorkshire said:

Good solutions, I like magnets and yes, a vernier is the item you need, but do you really need 1/10ths? In practice a half degree mark would probably do and you could 'eyeball' it for smaller amounts, it's surprising how accurately one can estimate visually - you'll need a light too don't forget.

Hadn't thought of lighting.  I have a spare head torch somewhere.  This is a MK1 design since I could print and laminate this size at home.  I think you are right on the half degree being more suitable.  I think it will land me close enough for most objects.  Thanks for the feed back.

38 minutes ago, Sunshine said:

This basically sums up what Mars looks like at the moment except maybe on a night of exceptional seeing, nice report.

I'm think about getting it printed on a t-shirt.

[apaulo]

Having done similar with a homemade dob, and also with the skytee 2 I now use. I am wondering how you are going to see the dial when the telescope is in the way.  a setting circle is a big plus, i personally would not be without it. When i made mine i had a local sign maker print me of a protractor to suit my base, the markings are quite far apart and a point can split them. Also when setting up its important the dob is as level as you can get it. Or close as. The same goes for aligning it with polaris.  I hope this is of help.

[Ratlet]

1 hour ago, apaulo said:

Having done similar with a homemade dob, and also with the skytee 2 I now use. I am wondering how you are going to see the dial when the telescope is in the way.  a setting circle is a big plus, i personally would not be without it. When i made mine i had a local sign maker print me of a protractor to suit my base, the markings are quite far apart and a point can split them. Also when setting up its important the dob is as level as you can get it. Or close as. The same goes for aligning it with polaris.  I hope this is of help.

That's the plan long term.  This is more of a proof of concept and will involve me tilting the tube a bit.  I'm not going to be able to get a big enough one printed for a couple weeks.  This should hopefully let me test out the principle.  The setting circle would be on the top section of the base.

Longer term I'd like to rebuild the base out of varnished plywood.  This is purely aesthetic.  But I would have a cut out section on the side where the focuser is so I can have the pointer at a convenient position relative to the focuser.  There are a couple designs on cloudy nights which do this setup well I think.

[apaulo]

I understand now. The varnished plywood base would look smart. good luck with the project, it would be good to see the finished mount.