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mwedel
sage
Reged: 12/16/07
Posts: 336
Loc: Claremont, CA
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I thought it would be cool to get a list of inexpensive accessories together, for those who want their GScopes fully tricked out. There are probably cheaper alternatives out there for some of these things, and loads of stuff I haven't thought of, so feel free to add to the list, edit it, pass it along, etc.
Tripods
Digital Concepts TR-60N, $9.29 on Amazon.
http://www.amazon.com/Digital-Concepts-TR-60N-Camera-Carrying/dp/B000093UDQ/
Davis & Sanford Traveler, $14.91 on Amazon.
http://www.amazon.com/Davis-Sanford-TRAVLR-Traveler-Tripod/dp/B00000JI48/
Eyepieces
Kellner eyepiece kits from $3.50 (from $17.50 assembled), Plossl kits from $5.50 (from $22.50 assembled), at Surplus Shed
http://www.surplusshed.com/pages/category/eyepiecessets_1.html
OWL Astronomy used to have some killer deals on EPs, like OWL Black Knight Super Plossls for $18.95-22.95, but it's been a couple of months since I've been there and I can't get the link to work tonight. I hope it's just a temporary glitch.
http://www.owlastronomy.com/superplossl.htm
Diagonals
1.25" Mirror Star Diagonal, $10.75 at Surplus Shed
http://www.surplusshed.com/pages/item/l2177.html
Antares 1.25" Mirror Star Diagonal, $18.95 at Hands on Optics
http://handsonoptics.com/
Clear skies!
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XT10
XT6
Astroscan
orange tube C90
15x70
10x50
10 Minute Astronomy
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Zoeff
sage
Reged: 06/10/09
Posts: 434
Loc: Haarlem, Netherlands
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Just a notice - It might not be possible to get the eyepiece into focus if there is a star diagonal in place. I can't remember if this is for infinity or for things relatively closeby.
Otherwise, nice list. 
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Telescope: C8 XLT with a Long Perng 100mm f/6 doublet on a NEQ6 Pro SynScan.
Accessories: Hyperion 36mm, GSO 32mm, E-lux 25mm, Hyperion 8mm,
DBK 41AU02.AS, 2x & 5x Barlow, 0.63x Focal Reducer, Solar Filter, UHC Filter.
My (astro-)photos can be found on flickr.
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Elias_Jordan
member
Reged: 12/26/08
Posts: 74
Loc: Derby, Kansas
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Problem with the Diagonal is that the GS doesn't have enough "in" focus for Celestial and Most non Celestial Objects. (Anything far away). I've tried 20 or more already....
Cool List!
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PiperKev
sage
Reged: 12/19/06
Posts: 202
Loc: Grafton, OH
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Another CNer, erick, has come up with a way to use a modified diagonal with the Galileoscope:
http://www.iceinspace.com.au/forum/showthread.php?t=47260
Cheers,
Kevin
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Orion SkyQuest f/8 XT6 Classic
Sears 4-6333 60mm f/15 refractor
TeleVue Plossls: 32mm, 11mm
Orion Sirius Plossls: 25mm, 20mm
Astro-Tech Paradigm 15mm, 12mm, 8mm
TMB Planetary II: 5mm
Faworski Orthos: 16.8mm, 10.5mm, 7mm
Celestron Ultima 2x barlow
Orion LaserMate Deluxe + Meade 126 2x barlow
Telrad
Oberlin, OH Clear Sky Clock
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PiperKev
sage
Reged: 12/19/06
Posts: 202
Loc: Grafton, OH
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Well, I've just bought a Giant Mars Eye finder to try out on mine since it's really difficult for me to use the "rifle" sights that are part of the scope. Should be interesting to see if it helps!
Cheers,
Kevin
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Orion SkyQuest f/8 XT6 Classic
Sears 4-6333 60mm f/15 refractor
TeleVue Plossls: 32mm, 11mm
Orion Sirius Plossls: 25mm, 20mm
Astro-Tech Paradigm 15mm, 12mm, 8mm
TMB Planetary II: 5mm
Faworski Orthos: 16.8mm, 10.5mm, 7mm
Celestron Ultima 2x barlow
Orion LaserMate Deluxe + Meade 126 2x barlow
Telrad
Oberlin, OH Clear Sky Clock
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GregAlt
member
Reged: 06/23/09
Posts: 32
Loc: Seattle, WA, USA
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In the other thread, I mentioned a $14 plastic blueprint tube with shoulder strap that is a good fit for a carrying case:
http://v5.britlink.com/BL5/DesktopDefault.aspx?TabID=44829&Alias=thecompleteline&ItemID=1890033
Any recommendations on eyepieces or barlows? Sure I could spend $100+ and push the limits of what the galileoscope could do, but I figure you'd quickly reach diminishing returns. What's the sweet spot for wow-factor compared to the existing plastic lenses but on a budget?
It looks like for $40+shipping you could get both a replacement eyepiece and barlow from the Owl link above. Or maybe it would make more sense to just spend $18 for either the 10mm or 6.5mm eyepiece.
My (newbie) sense is the 6.5mm eyepiece would give me the most bang for the buck. I'd still have the options of 25x and 50x magnification with the plastic lenses, and the 25x seems decent by itself. But for looking at planets, I'd get a slight boost in magnification up to 77x, and it should be noticeably improved viewing with fewer and better quality lenses in the light path.
I'd also imagine that the limitations of the galileoscope would mean that it wouldn't necessarily be worth it to invest much more money. Would I be right to think that the biggest wow-factor jump would be in spending the $18, and that throwing another $50-$100 into an eyepiece/barlow would have less noticeable marginal improvement? And if we get up much more beyond that, then it would make more sense buying a whole new telescope with a bigger aperture.
Though some quick searching suggests eye relief would be a problem with such a short plossl.
Is there a workable option that closer to $20 than $40?
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Orion XT8i - 8" f/5.9
Nikon Action 10x50 Binoculars
Galileoscope 50mm f/10 (20mm ep + 2x barlow)
25mm, 10mm Sirius Plossl eyepieces (1.25")
12.5mm Black Knight OWL Super Plossl
2x Knight OWL Barlow
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hamelph
newbie
Reged: 07/07/09
Posts: 3
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For those in Canada, for the tube, you can try Omer Desserres, art supplies store. I bought this yesterday:
http://216.139.219.73/SITES/deserresca/index.asp?C=1&DB=012_deserresca&M=1&L=F&categorie=T2329
It fits perfectly. I used the foam packing from the lenses to pad the bottom of the tube.
Philippe
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erick
super member
Reged: 11/21/07
Posts: 104
Loc: Bacchus Marsh, Australia
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I've picked up a tube from my post office. Cut the length down. Stuffed some "bubble-wrap" in the ends and pushed in the tube endcaps - indestructible carry case!
Have been experimenting with mounting the GS on a small tracking mount (an old Meade ETX base). Need a better support than the tripod mount. Was tracking nicely but with a bit of wind the other night Jupiter looked like a big mother firefly with four little baby fireflies buzzing around the FOV!  I have a design in mind - a bit of aluminium, some wood with V cuts, a few screws, some rubberbands.....
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PiperKev
sage
Reged: 12/19/06
Posts: 202
Loc: Grafton, OH
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Here's a question: Has anyone found a dust cap/lens cap that will work to protect the objective? I stopped by a local camera shop here in NE Ohio, and the "snap on" lens caps they had were 62mm, which was too small, and 67mm, which was too big. Right now, I have a Ziplock bag hanging over the dew shield just to keep dust off of the objective, but it looks tacky...
Cheers,
Kevin
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Orion SkyQuest f/8 XT6 Classic
Sears 4-6333 60mm f/15 refractor
TeleVue Plossls: 32mm, 11mm
Orion Sirius Plossls: 25mm, 20mm
Astro-Tech Paradigm 15mm, 12mm, 8mm
TMB Planetary II: 5mm
Faworski Orthos: 16.8mm, 10.5mm, 7mm
Celestron Ultima 2x barlow
Orion LaserMate Deluxe + Meade 126 2x barlow
Telrad
Oberlin, OH Clear Sky Clock
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PiperKev
sage
Reged: 12/19/06
Posts: 202
Loc: Grafton, OH
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Anyone??
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Orion SkyQuest f/8 XT6 Classic
Sears 4-6333 60mm f/15 refractor
TeleVue Plossls: 32mm, 11mm
Orion Sirius Plossls: 25mm, 20mm
Astro-Tech Paradigm 15mm, 12mm, 8mm
TMB Planetary II: 5mm
Faworski Orthos: 16.8mm, 10.5mm, 7mm
Celestron Ultima 2x barlow
Orion LaserMate Deluxe + Meade 126 2x barlow
Telrad
Oberlin, OH Clear Sky Clock
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Zoeff
sage
Reged: 06/10/09
Posts: 434
Loc: Haarlem, Netherlands
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I think you'll have to make one yourself.
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Telescope: C8 XLT with a Long Perng 100mm f/6 doublet on a NEQ6 Pro SynScan.
Accessories: Hyperion 36mm, GSO 32mm, E-lux 25mm, Hyperion 8mm,
DBK 41AU02.AS, 2x & 5x Barlow, 0.63x Focal Reducer, Solar Filter, UHC Filter.
My (astro-)photos can be found on flickr.
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Elias_Jordan
member
Reged: 12/26/08
Posts: 74
Loc: Derby, Kansas
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Need something thats 63mm, thats how big the inside of the Dew Cap is...Hmm lets see if I can find something, or build something...
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GregAlt
member
Reged: 06/23/09
Posts: 32
Loc: Seattle, WA, USA
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So looking at the owl site again...
They have a deal for 3 eyepieces and a 3x barlow for $70. It seems like a lot of money to throw at a galileoscope, but if I ever upgraded to a 6" dob like everyone seems to think is a reasonable next step, the eyepieces would be usable and not too inferior of quality.
If that's true, then which to pick? They have 4, 6.5, 10, 12.5, 15, 20, 25, 30, 40mm
It sounds like the maximum usable magnification for the galileoscope is about 100x. If you got the 15, 20, and 25mm eyepieces with a 3x barlow, that would give you magnification of 20, 25, 33, 60, 75, and 100x. Alternatively, you could get 12.5, 15, and 20mm which would give you 25, 33, 40, 75, 100, and 120x.
Or, for $39, I can skip the combo deal and just get a 2x and a 12.5mm. Then I'd have 25x, 40x, 50x, and 80x - with a combination of the new 12.5mm and new 2x barlow and the stock 20mm eyepiece. Probably reasonable since the stock eyepiece isn't that bad, and there's probably not much benefit having more than 80x magnification.
Any thoughts? Also, standard 1.25" eyepieces fit, but if I'm looking at something high in the sky, would I have to worry about them dropping right out of the galileoscope? Or do they fit snug enough not to worry?
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Orion XT8i - 8" f/5.9
Nikon Action 10x50 Binoculars
Galileoscope 50mm f/10 (20mm ep + 2x barlow)
25mm, 10mm Sirius Plossl eyepieces (1.25")
12.5mm Black Knight OWL Super Plossl
2x Knight OWL Barlow
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Zoeff
sage
Reged: 06/10/09
Posts: 434
Loc: Haarlem, Netherlands
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Quote:
So looking at the owl site again...
They have a deal for 3 eyepieces and a 3x barlow for $70. It seems like a lot of money to throw at a galileoscope, but if I ever upgraded to a 6" dob like everyone seems to think is a reasonable next step, the eyepieces would be usable and not too inferior of quality.
If that's true, then which to pick? They have 4, 6.5, 10, 12.5, 15, 20, 25, 30, 40mm
It sounds like the maximum usable magnification for the galileoscope is about 100x. If you got the 15, 20, and 25mm eyepieces with a 3x barlow, that would give you magnification of 20, 25, 33, 60, 75, and 100x. Alternatively, you could get 12.5, 15, and 20mm which would give you 25, 33, 40, 75, 100, and 120x.
Or, for $39, I can skip the combo deal and just get a 2x and a 12.5mm. Then I'd have 25x, 40x, 50x, and 80x - with a combination of the new 12.5mm and new 2x barlow and the stock 20mm eyepiece. Probably reasonable since the stock eyepiece isn't that bad, and there's probably not much benefit having more than 80x magnification.
Any thoughts? Also, standard 1.25" eyepieces fit, but if I'm looking at something high in the sky, would I have to worry about them dropping right out of the galileoscope? Or do they fit snug enough not to worry?
The Galileoscope is an f/10, while most dobs are about an f/6 or so. This means that they've got a much wider field of view compared to the Galileoscope. Eyepieces that work for the GS might not work for the dob you're going to buy.
Personally, I'd recommend the second option you considered (without a future dob in mind). I don't recommend spending a lot on your first set of eyepieces, you might regret it later. Also, anything higher than 80x will make it extremely difficult to focus.
I wouldn't worry too much about eyepieces falling out, they do fit in quite nicely with friction alone. Unless of course you bought some heavy and/or expensive one...
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Telescope: C8 XLT with a Long Perng 100mm f/6 doublet on a NEQ6 Pro SynScan.
Accessories: Hyperion 36mm, GSO 32mm, E-lux 25mm, Hyperion 8mm,
DBK 41AU02.AS, 2x & 5x Barlow, 0.63x Focal Reducer, Solar Filter, UHC Filter.
My (astro-)photos can be found on flickr.
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Robert Cook
super member
Reged: 07/23/09
Posts: 101
Loc: San Diego County, California
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Zoeff wrote:
Quote:
The Galileoscope is an f/10, while most dobs are about an f/6 or so. This means that they've got a much wider field of view compared to the Galileoscope.
Are you sure? What you say about focal ratio would be true with all else being equal, but all else is not equal. In visual astronomy, the width of a telescope's maximum true field of view is ultimately determined by its focal length, the width of its focuser, and the width of the exit pupil. The Galileoscope's focal length is only 500 mm compared to the ~1200 mm of typical Dobs, and its maximum field of view with its 1.25" focuser is probably around 3.2 degrees (using a 32 mm Plössl with a 50 degree apparent field of view and a 3.2 mm exit pupil). This would be tough for a typical Dob to match even if we gave it a 2" focuser and ignored exit pupil width, which is actually the most severe limiting factor here.
By the way, although tiny tabletop Dobs may be able to match or exceed the Galileoscope in maximum field of view, they wouldn't be that much of an upgrade overall, if they are at all.
Zoeff wrote:
Quote:
Eyepieces that work for the GS might not work for the dob you're going to buy.
That's a valid consideration regardless of anything I've said above.
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Zoeff
sage
Reged: 06/10/09
Posts: 434
Loc: Haarlem, Netherlands
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I meant with the same eyepieces.
Or am I missing something here? 
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Telescope: C8 XLT with a Long Perng 100mm f/6 doublet on a NEQ6 Pro SynScan.
Accessories: Hyperion 36mm, GSO 32mm, E-lux 25mm, Hyperion 8mm,
DBK 41AU02.AS, 2x & 5x Barlow, 0.63x Focal Reducer, Solar Filter, UHC Filter.
My (astro-)photos can be found on flickr.
Edited by Zoeff (07/31/09 03:46 AM)
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Robert Cook
super member
Reged: 07/23/09
Posts: 101
Loc: San Diego County, California
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Zoeff wrote:
Quote:
I meant with the same eyepieces.
Or am I missing something here?
With the same eyepiece, the true field of view can be calculated by dividing the focal length of the telescope by the focal length of the eyepiece in order to get the magnification, and then dividing the apparent field of view in the eyepiece by the magnification. Using a 32 mm eyepiece with a 50 degree apparent field of view, for example, the Galileoscope would have a true field of view of 50 / (500 / 32) = 3.2 degrees, while a typical 8" f/6 Dob would have a true field of view of 50 / (1200 / 32) = ~1.3 degrees, which is narrower rather than wider despite the faster focal ratio.
A telescope's focal ratio does play a part in the equation, but only in combination with the width of the objective lens/mirror in determining the telescope's focal length. In the end, although it may seem strange at first, only the focal length matters when determining things like magnification and true field of view. The focal ratio is handy for calculating the width of the exit pupil by dividing the focal length of the eyepiece by the telescope's focal ratio. The exit pupil in turn limits the eyepiece focal lengths that can be used with a telescope because you'd want to be able to fit the whole image through the pupil of your eye.
All else being equal, it is true that a lower (faster) focal ratio results in a wider field of view because the image at the focal plane is smaller. However, in this case there is a large difference between the sizes of the objectives, which ultimately causes the image in typical Dobs to be larger than that of the Galileoscope (a larger objective means a larger image and more magnification) and therefore narrower in field of view. The only way to make them equivalent in maximum true field of view would be to use a 76.8 mm eyepiece, but then you would need pupils about four times larger than the ones you have, as well as a focuser larger than 2".
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Zoeff
sage
Reged: 06/10/09
Posts: 434
Loc: Haarlem, Netherlands
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Brain. It just died.
I'll have to study your post for a while before I understand it...
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Telescope: C8 XLT with a Long Perng 100mm f/6 doublet on a NEQ6 Pro SynScan.
Accessories: Hyperion 36mm, GSO 32mm, E-lux 25mm, Hyperion 8mm,
DBK 41AU02.AS, 2x & 5x Barlow, 0.63x Focal Reducer, Solar Filter, UHC Filter.
My (astro-)photos can be found on flickr.
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GregAlt
member
Reged: 06/23/09
Posts: 32
Loc: Seattle, WA, USA
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Here's an online telescope calculator that puts it all together in a way that makes some sense to me:
http://www.stargazing.net/naa/scopemath.htm
Putting in the numbers for a galileoscope and a 6" f/6 dob suggest the optimum eyepieces for a galileoscope would be 20mm-40mm and for the dob would be 12mm-24mm, with the usable range (not counting focuser length, I guess, and assuming my 38 year old eyes) being 5mm-63mm for the galileoscope and 3mm-40mm for the dob.
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Orion XT8i - 8" f/5.9
Nikon Action 10x50 Binoculars
Galileoscope 50mm f/10 (20mm ep + 2x barlow)
25mm, 10mm Sirius Plossl eyepieces (1.25")
12.5mm Black Knight OWL Super Plossl
2x Knight OWL Barlow
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Robert Cook
super member
Reged: 07/23/09
Posts: 101
Loc: San Diego County, California
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Zoeff wrote:
Quote:
I'll have to study your post for a while before I understand it...
Feel free to ask questions about anything I said, and I'll try my best to explain. Basically, true field of view depends on the aperture as well as the focal ratio. Multiply the two together and you get the telescope's focal length, which conveniently takes both factors into account simultaneously. The Galileoscope's focal length is 500 mm (50 mm aperture times focal ratio 10) while a typical Dob's focal length is 1200 mm (200 mm aperture times focal ratio 6), which means that the Galileoscope has a wider field of view (the shorter the focal length, the wider the true field of view).
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