Large sunspot visible

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  • #26
sophiecentaur
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Those are AU$ prices ..... what make and model scope do you have ?
I bought a sky watcher dobs 200p on eBay.
It looks like it has had an easy life and the optics seem to be lined up right. The two kit lenses are a bit naff, I think. I just bought a 2 inch 32mm Panavision SWA lens which is so much better. It's contrasty and crisp and pretty flat over the field. That beehive cluster was stunning with my eye flat against the eyepiece. I never realised that magnification isn't everything when looking at the sky. Structures are just as interesting as tiny details. Stellarium is my friend at the moment.
Of course, the Dobs lacks any screw adjustments for direction and I have started to learn how to star-hop, to get to stuff, even with the finder scope. The pinwheel galaxy is directly overhead and the altaz mount is a total pig at that angle; you have to get used to a completely non-cartesian idea of moving around a cartesian looking picture. The two degrees of freedom that you have, do really unexpected things with what you see and even with a right angle finder scope, you still have to lay on the ground to point it in the right sort of direction to start with.
All this is totally off - topic, of course.
 
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  • #27
davenn
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I bought a sky watcher dobs 200p on eBay.
It looks like it has had an easy life and the optics seem to be lined up right. The two kit lenses are a bit naff, I think. I just bought a 2 inch 32mm Panavision SWA lens which is so much better. It's contrasty and crisp and pretty flat over the field. That beehive cluster was stunning with my eye flat against the eyepiece.
if this is the beast ? .....
https://www.firstlightoptics.com/dobsonians/skywatcher-skyliner-200p-dobsonian.html

that should keep you out of trouble for some time :smile:

I never realised that magnification isn't everything when looking at the sky. Structures are just as interesting as tiny details.
indeed !! .... magnification is more important for planetary observing because of their small angular size
for most deep space objects, lower magnification is more important


Stellarium is my friend at the moment.
Of course, the Dobs lacks any screw adjustments for direction and I have started to learn how to star-hop, to get to stuff, even with the finder scope.
This is really important !! I spent the first 30 years of my amateur astro life star hopping and in those days using paper maps. It's the ONLY way to really get to know your way around the sky. It's a valuable skill. Even tho I have a GOTO ( controller guided) scope these days, it mainly gets used for being able to quickly get between objects I want to photo ... on my own or when I take a group out with me. For finding things like comets, nova etc, I still resort to my well learned star hopping skills :smile:

The pinwheel galaxy is directly overhead and the altaz mount is a total pig at that angle; you have to get used to a completely non-cartesian idea of moving around a cartesian looking picture. The two degrees of freedom that you have, do really unexpected things with what you see and even with a right angle finder scope, you still have to lay on the ground to point it in the right sort of direction to start with.
You will get used to it, you may find making a 0.5 metre high platform to sit the scope/ mount on eases the difficulty of use Last August, I bought a new camera for doing astrophotography, the Canon 700D, one of its major selling points to me is that it has a swivelling LCD panel, unlike my main camera, the Canon 5D MK3. Now I don't have to kink my neck/head into weird angle to try and see the screen when doing focussing etc, it is so much more fun to use


All this is totally off - topic, of course.
Was my thread, the main topic had been well discussed. I don't mind it going off track if it means I can pass on some encouragement for people to get out there and have some astro fun :smile:


cheers
Dave
 
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  • #28
sophiecentaur
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you may find making a 0.5 metre high platform to sit the scope/ mount on eases the difficulty of use
I was already considering that. It would make a 'decorative' seat for the garden when the Dobs was not there. Two for the price of one!!

I have also considered how easy it might be to use a different base, with an inclined bearing to turn the Dobs mount into a polar mount. As I do not intend to cart the scope around the World, that base could be permanently fixed outside, pointing N/S and I would only need to take the scope barrel indoors. I can't imagine it would be possible just to park the Dobs on a sloping platform; the azimuth bearing wouldn't stand it. I have already found it inconvenient to keep up with Jupiter as it marches across my view, using both axes. (A pukka conversion to polar mount with Goto for my dobs is out of the question for a while - until I have made much better use of it)
 
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  • #29
Dotini
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62d9152e375bdf59c265689dd29c7293.jpg
 
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  • #31
sophiecentaur
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Now that is a good example of perspective!
If I go the the expense of buying a solar filter for my 200mm Dobs, is that the sort of picture I should be expecting? That would mean an extra potential half days gazing every day.
 
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If I go the the expense of buying a solar filter for my 200mm Dobs, is that the sort of picture I should be expecting? That would mean an extra potential half days gazing every day.
I have to claim total ignorance when it comes to this question. I'm pretty sure the image Dotini posted is from NASA's SDO so that would be tough to compete with from earth. I would think Dave, Russ, Dotini or Andy would be able to recommend the best case answer for choosing a filter. :smile:
 
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Dotini
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  • #34
sophiecentaur
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And talking of Solar Filters. There are filters available on eBay that fit onto the small hole in the cover of my 200p. They also fit on the finder scope. Are they worth the bother? The resolution can only be around a tenth of the full mirror. (Or rather, ten times the angular resolution)
 
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Got that pic off Yahoo
Cool, that's an interesting shot.
 
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  • #36
Dotini
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Cool, that's an interesting shot.
Heh heh! Almost as if the sun were opening like a magnetic flower in greeting to its little relative, Mercury. :cool:
 
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Heh heh! Almost as if the sun were opening like a magnetic flower in greeting to its little relative, Mercury. :cool:
True, I know its only a matter of perspective but it looks like that flare could engulf mercury.
 
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  • #38
Andy Resnick
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And talking of Solar Filters. There are filters available on eBay that fit onto the small hole in the cover of my 200p. They also fit on the finder scope. Are they worth the bother? The resolution can only be around a tenth of the full mirror. (Or rather, ten times the angular resolution)
I would not mess around with kludging a solar filter. Since you are just starting out, at the so-cheap-it's-practically-free end of the spectrum, try a mylar blanket- the sort that comes in first aid kits- secure it to the barrel with an elastic band (or some Kapton tape). I tried a mylar balloon, but there was a very visible 'weave' type pattern so I was out $2.50 US. After that, I scrounged up a reflective ND 4 filter that I insert where the lens filters go, attaching it with some Kapton tape. The reflective filter comes first, before any polarizer/UV blocker/etc. Important- make sure it's a *reflective* filter, not an absorbing filter.

If you want to try spectral solar filters, they are incredibly expensive sub-angstrom width temperature-controlled etalons. I don't have those. I tried using a rescued 'narrowband' filter (+/-10nm) from an old microscope in conjunction with the ND 4, but the spectral width is still too broad.

As for the finder scope, I wouldn't bother if you are not using the finder- in fact, you may want to remove the finder for solar viewing just in case you happen to glance through it. It's not like you will have trouble finding the sun.....
 
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  • #39
davenn
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I would not mess around with kludging a solar filter. Since you are just starting out, at the so-cheap-it's-practically-free end of the spectrum, try a mylar blanket- the sort that comes in first aid kits- secure it to the barrel with an elastic band (or some Kapton tape).

yup, read my post #23 :wink::wink:

Dave
 
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