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Aperture Fever Strikes!


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With @cotterless45 buying up all the supplies of aperture fever pills, I find myself struck down with the desire for a new scope ;) The only scope I've ever known is my SkyWatcher Explorer 130M on an EQ2 mount. It's been a great scope beginner scope for me and continues to serve me well. It's good as a grab and go scope. I can easily move it around the garden to find the best view through the various obstacles. Being mounted on a tripod has helped with seeing over the garden fence to objects low on the horizon. It's gone on a few dark sites trips and I've been really pleased with how much can be seen through it. The biggest frustration of this scope is the EQ mount. I really struggle with anything around the zenith. Sometimes I end up leaning over and trying not to knock the counterweight whilst looking through the eyepiece. It's not very comfortable. 

So why do I want a new scope? I'd like to see more detail and more fainter objects. I really enjoy nebulae and galaxies and would like to pick up structure within them. I'd also like to pick up more planetary detail than I can with my current scope.

My first thought is a 10", or maybe even 12", dob. However, I don't know much about refractors or other telescope types to know if they might better suit my needs or budget. I know dobs are often talked about as being particularly good value for money. Moving a big dob around does worry me a little. 

My budget is likely to be around £400 - £500. I'm happy to buy secondhand to get a bit more for my money. My only other consideration is whether my existing eyepieces will work well in the new scope. I know the SkyWatcher 10" dob is F4.7 which is below the F5 that the BST Starguiders are rated for. I think my other eyepieces will probably be ok. I'm also open to saving a little longer to up the budget and get the right scope if necessary.

I've got a couple of months before I'll be buying anything so plenty of time to think it over. Any and all advice/suggestions greatly appreciated :) 

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Hi Neil,

You can't really go wrong with a 10inch dob. It's easy to move (in two bits or even for short hops as one). BST starguiders seem to work fine with the f4.7 ratio, but there are lots of alternative EPs if you so desire (the Explore Scientific 82 degree range is very good). 12 inch Skywatchers are also manageable, but are pushing it a little.

10-inchers seem to come up for sale regularly, for around £300, leaving you plenty in budget for a nice ES eyepiece ...

Best advice would be to see of you can take a go on one, as it were, at a star party / club night.

Kev

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1 minute ago, alanjgreen said:

A nice Dob is calling you :)

Have you got a garage?

What are your thoughts on storage space?

 

Whats your garden like? is it flat?

 

Will the dob be going in your car?
 

I do have a garage where I will most likely store it. Garden is pretty flat. I have a brick weave path running the length of it. Dob will definitely be going in the car. It's a people carrier so plenty of room in there.

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Well Neil, I'm thinking along similar lines.  I'm very happy with ST120 frac - dead easy to use, and great widefield views.  The 8SE SCT GoTo is brilliant.  But I also want a light bucket to hopefully improve my views of fuzzies -  I have agonised for ages about which one to get: Skywatcher, Orion Optics, Bresser, and have settled on a Skywatcher, probably 12".  I know it is huge, and there 's no more room in the house, but I can dream.....  I reckon my EPs will (mostly) be fine in an f/4.9, and  - I believe - you can get away without a coma corrector at that speed.  I just don't fancy extra elements/glass in the optical path, which is why I never use a Barlow.

I know what you mean about the Eq mount - not for me, I'm afraid!

Take your time over the decision, look around, get advice, and above all, have fun!

Doug.

 

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Neil,

Even an 8 inch mirror will collect more than twice as much light as the 130mm mirror. You WILL notice this at the eyepiece.

A 10 inch will gather more than 3.5x more light, this will be beyond comparison to a 130mm.

So it seems that PORTABILITY should be the main concern as a scope gathering dust is not as good as a 130mm

 

Since most telescope objectives are circular, the area = pi× (diameter of objective)2/4, where the value of pi is approximately 3.1415. For example: a 40-centimeter mirror has four times the light-gathering power as a 20-centimeter mirror [(pi402/4) / (pi202/4) = (40/20)2 = 4].

pi x 130*130 /4 = 13272 (130mm scope)

pi  x 200*200 /4= 31415 (200mm scope 8")

31415/13272 = 2.36x more light than a 130mm (200mm scope 8")

pi  x 250*250 /4= 49085 /13272 = x3.69 more light than a 130mm (250mm scope 10")

pi  x 300*300 /4 = 70683 /13272= x5.32 more light than a 130mm (300mm scope 12")

( I included the 12" more to fuel your fever than meaning you will be able to manage to manhandle it around the garden ) - do you live near a scope shop where you could go view some dobs for size?)

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2 minutes ago, cloudsweeper said:

Well Neil, I'm thinking along similar lines.  I'm very happy with ST120 frac - dead easy to use, and great widefield views.  The 8SE SCT GoTo is brilliant.  But I also want a light bucket to hopefully improve my views of fuzzies -  I have agonised for ages about which one to get: Skywatcher, Orion Optics, Bresser, and have settled on a Skywatcher, probably 12".  I know it is huge, and there 's no more room in the house, but I can dream.....  I reckon my EPs will (mostly) be fine in an f/4.9, and  - I believe - you can get away without a coma corrector at that speed.  I just don't fancy extra elements/glass in the optical path, which is why I never use a Barlow.

I know what you mean about the Eq mount - not for me, I'm afraid!

Take your time over the decision, look around, get advice, and above all, have fun!

Doug.

 

Thanks Doug. It's nice to know that you've got a frac and SCT but still want a dob. Did you think much about 10" vs 12"? 

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http://www.astrobuysell.com/uk/propview.php?view=133848

This scope is in NORFOLK near you :)

Superb Explore Scientific 10" Ultra Light Dobsonian with 30mm ES eyepiece and upgrades *** final reduction
Post review, this excellent ES truss-tube 10-inch Dobsonian possesses particularly fine optics and comes with an upgraded finder in the form of a Celestron StarPointer Pro and the Explore Scientific counterweight kit. With original packing, UK postage is included. I will also bundle a new 2-inch ES 30mm 70 deg. AF eyepiece. A particularly reluctant sale, but I must thin the herd.

https://www.telescopehouse.com/explore-scientific-ultra-light-10-dobsonian.html?gclid=EAIaIQobChMIosCN75qA2QIV7r_tCh1JfwbkEAQYASABEgIbZ_D_BwE

https://www.harrisontelescopes.co.uk/acatalog/explore-scientific-ultra-light-10-dobsonian.html#SID=1644

You would have to read up on them. I dont know whether these are better than the skywatcher?? They look like they break down into smaller packages for moving about.

Alan

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25 minutes ago, alanjgreen said:

Neil,

Even an 8 inch mirror will collect more than twice as much light as the 130mm mirror. You WILL notice this at the eyepiece.

A 10 inch will gather more than 3.5x more light, this will be beyond comparison to a 130mm.

So it seems that PORTABILITY should be the main concern as a scope gathering dust is not as good as a 130mm

 

Since most telescope objectives are circular, the area = pi× (diameter of objective)2/4, where the value of pi is approximately 3.1415. For example: a 40-centimeter mirror has four times the light-gathering power as a 20-centimeter mirror [(pi402/4) / (pi202/4) = (40/20)2 = 4].

pi x 130*130 /4 = 13272 (130mm scope)

pi  x 200*200 /4= 31415 (200mm scope 8")

31415/14272 = 2.36x more light than a 130mm (200mm scope 8")

pi  x 250*250 /4= 49085 /13272 = x3.69 more light than a 130mm (250mm scope 10")

pi  x 300*300 /4 = 70683 /13272= x5.32 more light than a 130mm (300mm scope 12")

( I included the 12" more to fuel your fever than meaning you will be able to manage to manhandle it around the garden ) - do you live near a scope shop where you could go view some dobs for size?)

Thanks Alan. Portability is definitely one of my biggest worries. I’ve seen one the 8” SkyWatcher dobs aty local astronomy club. That looked pretty big but certainly manageable. It was put in a little hatchback. I know there’s a couple of 12” dob users there but I’ve not seen them yet. 

The ES scope looks really nice! Currently marked as sale pending so looks like I’ll be too late for that one. I’m not sure how well they’re regarded. Some research needed!

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6 minutes ago, Littleguy80 said:

The ES scope looks really nice! Currently marked as sale pending so looks like I’ll be too late for that one. I’m not sure how well they’re regarded. Some research needed!

See if you can contact him via email as he seems to be a scope reviewer! He can give you his conclusions after testing the scope...

http://www.nightskies.net/scopetest/index.html

email = ade@scopetest.com

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2 minutes ago, Astro Imp said:

Exciting times Neil, good luck with the search.

The scope pointed to by @alanjgreen is offered for sale by Ade Ashford so you can be sure it is in good condition and has been well looked after.

 

Thanks Alan, that’s really good to know. It’s always a nervous experience buying secondhand!

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3 minutes ago, Littleguy80 said:

Thank you! I’ve seen a few of these 12” Revelation dobs come up. Has anyone had any experience of them?

I would go for collapsible or truss tube for a 12" if you want to move it around. Solid tube would be a bit of a monster.

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30 minutes ago, Littleguy80 said:

Thanks Doug. It's nice to know that you've got a frac and SCT but still want a dob. Did you think much about 10" vs 12"? 

Yes Neil.  I convinced myself for a while that a 10" would be fine, but now feel that a bigger step is necessary.

8 to 10" - 56% more light; 8 to 12" - 125%.  I think that's what's called a no-brainer! 

The reason I want a Dob as well is that all three will serve different purposes - widefield, high mag and GoTo, deep sky.  (Don't tell Mrs Sweeper, but I also want a fourth 'scope, a dedicated solar jobby.  The filters I use with the frac are fine, but do not reveal much more than some nice sunspot detail.)

Doug.

 

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4 minutes ago, cloudsweeper said:

Yes Neil.  I convinced myself for a while that a 10" would be fine, but now feel that a bigger step is necessary.

8 to 10" - 56% more light; 8 to 12" - 125%.  I think that's what's called a no-brainer! 

The reason I want a Dob as well is that all three will serve different purposes - widefield, high mag and GoTo, deep sky.  (Don't tell Mrs Sweeper, but I also want a fourth 'scope, a dedicated solar jobby.  The filters I use with the frac are fine, but do not reveal much more than some nice sunspot detail.)

Doug.

 

I agree. I went from 8" SCT to 11" SCT and the difference was noticeable. I would not change from 8" to 10" either. Its got to be a 12" from an 8" starting point.

As an alternative to goto, consider "push to" or "equatorial platform" to bring a standard dob to life. Goto adds a lot of weight if you have to move it around. I feel that a large goto dob needs a permanent home.

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1 hour ago, Littleguy80 said:

I've got a couple of months before I'll be buying anything so plenty of time to think it over. Any and all advice/suggestions greatly appreciated :) 

I have a 10" f4.8 dob from OOUK that is VG but @John has a bit better set up with his f5.3 12" OOUK, which would be among the best all round scopes there is.  THe other night the VX10 easily went over 300x razor sharp on the moon, but I do have good seeing. If buying again I would have picked the f5.3 12".

Maybe John can chime in?

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24 minutes ago, alanjgreen said:

I agree. I went from 8" SCT to 11" SCT and the difference was noticeable. I would not change from 8" to 10" either. Its got to be a 12" from an 8" starting point.

Agree there. A 12" SW Flextube may be the portability solution. But more expensive.

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10” flextube is the way forward. For me, it is the perfect trade off between inches and useability. You can pick it up in one piece and move it around the garden relatively easily. It fits in the car.   And you can see loads!

12” will give you a bit more light grasp, but is getting big. 14”? May as well go for 16”......

If you are minted, Jetstream’s 12” OOUK is your baby. Otherwise it’s the 10” SW flextube.

Paul

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1 hour ago, alanjgreen said:

See if you can contact him via email as he seems to be a scope reviewer! He can give you his conclusions after testing the scope...

http://www.nightskies.net/scopetest/index.html

email = ade@scopetest.com

I emailed Ade as suggested. He’s written an in depth review of the scope for the February edition of Astronomy Now. The scope is due to be picked up this week by someone but he highly recommended the range

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1 hour ago, jetstream said:

I have a 10" f4.8 dob from OOUK that is VG but @John has a bit better set up with his f5.3 12" OOUK, which would be among the best all round scopes there is.  THe other night the VX10 easily went over 300x razor sharp on the moon, but I do have good seeing. If buying again I would have picked the f5.3 12".

Maybe John can chime in?

Thanks Gerry. I had a look on the ABS archives and these scopes do come up secondhand in my price range :) As @Paul73 noted, they’re quite pricey new!

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For purely visual dobs raw viewing power, ruggedness, and simplicity can't be beaten. Longer FL i.e. F5+ do not require daily collimation if the mirror cel and spider/flat holder are strong and hold the mirrors in place.

10 ins solid tubes are OK. 12 ins & more need more consideration regarding handling, transport and storage. If we get clearer night skies more frequently, I would like a 14-16 Flextube.

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