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Old 08-03-2021, 04:46 PM
mr2ns
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Guide me on Eyepieces & DSLR adapters

Hi Everyone.

I have had my scope for awhile. But I am now wanting to venture into photography.

My kit:

Nikon D600
Skywatcher 8 inch with Plossl eyepieces - 10, 25, 32mm. Plus a 2x barlow.

I would like to get a one or two additional eyepieces and an adapter for my camera.

-Can I get this at the same online store?
-Should I get the adapter from ebay?
-What adapters do I need - is it a T-Ring and T-Ring Adapter?
-Which eyepieces sizes should I invest in and what brand (budget around $150 per eyepiece)?
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  #2  
Old 08-03-2021, 07:25 PM
astro744
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You have a good spread of magnification if you include the Barlow. What do you feel you are missing with the eyepieces you have? Perhaps a larger apparent field than Plossls provide or do you want a larger true field of view?

I would presume you have a 2” focuser so perhaps a long focal length 2” eyepiece between 30 and 40mm with an apparent field 60-70 deg. to give you both a larger apparent field and maximise your true field of view. Note exit pupil is 8mm with the 40mm at f5 so only good for dark skies. As a low power finder eyepiece do not be too concerned about the large exit pupil but it will give low contrast under light polluted skies. Something around 30mm is better for your telescope to keep the exit pupil down a bit but you lose out on true field unless you go to say 80 deg apparent field. A few years ago the cheap 30mm/80 deg eyepiece was very popular (may still be) but note none of these cheap offerings come close in performance to something like a 31mm Nagler but of course none come close to the cost of the Nagler (yes the Nagler is worth it). I’m not familiar with what cheap offerings are available in 30/80 these days so perhaps someone else can help you here. This will give you greater apparent field and greater true field to complement your current selection.

Note eyepieces are not required for prime focus photography but are required for eyepiece projection (high power for planets) which just about no one does anymore favouring video capture with Barlows or Powermates and small chip cameras. You can use longer focal length and long eye relief eyepieces for afocal photography (digiscoping) but again this is not normally done with a DSLR but rather a mobile phone.

Your Skywatcher may have come with a 2” adaptor with T-thread in which case you only need a T-ring to match your camera brand. If not yes you need a T-adaptor with a 2” nosepiece one end and T-thread the other end and then a T-ring to match your camera brand. Don’t bother with a 1.25” T-adaptor if you have a 2” focuser as it will only vignette.

Edit. If your telescope is f6 then 40mm eyepiece for low power finder would be fine, (dark skies still better for contrast). Exit pupil=eyepiece focal length/telescope focal ratio.

Last edited by astro744; 08-03-2021 at 07:50 PM. Reason: Added last para.
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Old 08-03-2021, 10:14 PM
mr2ns
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Wow. Thanks for the response. I'm sorry but I would still consider myself a beginner... so bare with me.

I have some more info:
My eyepieces are 1.25" and 52 deg. I do have a 2 inch adapter which Ive never used. It looks like this though:
https://stargazerslounge.com/uploads...1453239355.jpg

So I dont think my camera would fit on that as the T ring wont screw on it it. Therefore I believe I need this - adapter and t ring?:
https://proastroz.com/products/dslr-...smart_campaign

The Barlow is GSO branded. I feel like it actually isnt any good (a little blurry) with the 10mm at all and sometimes not even the 25mm.

I think what I am looking for is both really - larger apparent field and larger true field of view. Perhaps a 2 inch and a recommendation on eyepieces is what I really need??? Is it 30/80 2 inch what I am looking for?

Yeah a Nagler is expensive. Any other suggestions in my price range?
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  #4  
Old 09-03-2021, 05:52 AM
astro744
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Is your telescope f5 (1000mm focal length) or f6 (1200mm focal length)? It makes a slight difference in eyepiece recommendations. Are your skies dark or have plenty of city lights? Are you young or not so young? Makes a difference in accomodation of field curvature in the eyepiece.

May I suggest the Bintel (GSO) 42mm and/or 30mm Superview eyepieces at $89.00 each and in stock. My son has the 15mm Superview and it is surprisingly good in his 80mm, f5 refractor. These eyepieces have 65-68 deg apparent field and the 42mm will give you maximum true field in your telescope. (Do not consider 50mm as exit pupil will be too large and to get same maximum true field, the apparent field will be less in the 50mm; good for SCTs for a brighter image at f10).

At 1200mm focal length you will get 2.2 deg with 42mm at 28x mag and 1.7 deg. with 30mm at 40 mag. The Pleiades will fit in 1.7 deg but slightly better framed in 2.2 deg. At 1000 mm focal length you get even more true field. There is enough difference between the 42mm and 30mm to warrant both in ones eyepiece kit. Do not Barlow these as their eye relief will be excessive. (A Powermate corrects this problem). I recommend shorter focal length in the same series and then a good quality 2x or 3x 1.25” Barlow (such as Tele Vue) to give you higher powers with the 15mm Superview.

The lower cost wide field (any low cost on the market) will typically have some field curvature. This is an aberration that can be corrected simply by focussing. It is where the outer part of the field is ever so slightly at a different focus than the inner. A young eye can accomodate this but not so much an older one. Field curvature was very noticeable on the 30mm, 80 deg eyepiece I had purchased and this in my f6.4 reflector. I then invested in some Tele Vue and never looked back. I’m not sure what the 30mm, 68 deg Superview is like but for $89.00 I think it will pleasantly surprise you. I would consider the 42mm too for the 2.2 deg true field.

Now if you didn’t want to go the low power route you could also consider replacing, (one at a time as budget allows) your current Plossl set with a better quality Plossl set such as what Tele Vue offer including their 2x and 3x 1.25” Barlow’s. Don’t get 2” Barlow from any brand as long focal length eyepieces require a Powermate to maintain eye relief. It becomes a heavy solution that can be better achieved other ways.

As for the camera adaptor, yes that will work. Note you can find cheaper on Amazon Au. I see you have a full frame camera. Not all T-rings are the same as somehave a wide opening better suited for full frame. The standard one will work but you get a little vignetting. Whichever T-ring you get you want the 2” T-adapter.

Also get yourself a2”-1.25” flat top adapter (about 10mm thick), not the one that comes with most 2” Barlows and has a recessed screw. That way you can permanently use the 2” Skywatcher adapter and slip in the 2”-1.25” when using 1.25” eyepieces.

I actually thought the Skywatcher came with a separate low profile photo adaptor with T-thread and all you need is the T-ring as this gives you the back focus you need for your camera otherwise you may not reach focus with your camera. Raymo on this forum is the Skywatcher guru and may advise better here so put off buying the T-adaptor for now as you may need a different Skywatcher piece. (You can get a T-ring for your camera).

Edit:
See https://www.bintel.com.au/product/bi...v=322b26af01d5

Last edited by astro744; 09-03-2021 at 06:47 AM. Reason: added link
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  #5  
Old 09-03-2021, 08:27 AM
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Allan_L (Allan)
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on my SW, the 1.25" eyepiece holder unscrews to reveal a T-Thread so no adaptor is needed.
All you need is the T-ring for your particular DSLR.
Good luck with it.
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Last edited by Allan_L; 09-03-2021 at 08:52 AM.
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  #6  
Old 09-03-2021, 04:52 PM
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1200mm focal length. 40mm for me would be too wide. I have a 40mm plossl and it is too wide at 819mm focal length. You are a bit less than half again focal length. I find 16/17.5-20mm very pleasant at 819mm focal length.
The sweet spot for me. 12.5mm also looks nice but 5mm is too high a mag and I see eye floaters.

So that would equate to 20-25mm eyepieces for your scope to get a nice comfortable mag. You might want a shorter focal length for planets, perhaps around 7.5 to 10mm. The TMB Planetary 11 eyepieces sell for about AUD$53 on ebay and are outstanding for the price.

20-25. I have a 25mm dual ED lens that is well made and is quite good. Not in the same league as the very high end eyepieces like Baader Morpheus, Televue Nagler or Ethos or APM.

An APM 20mm XWA would be sensational. I have the 9 and the 20 and they are wow eyepieces. But they are more than $150.

There are probably nice eyepieces from Celestron, Orion, perhaps GSO for that price. Best to check reviews on Cloudy Nights. But I would rather have one wow eyepiece than 3 ordinary eyepieces for the same total cost.

Greg.
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Old 09-03-2021, 07:18 PM
astro744
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What you mean by too wide? It’s true field you are gaining and 2 deg field is a nice match to a Telrad as it matches the centre ring and you can get away without a finder. Power is low and sky brightness higher unless sky is very dark but for a few objects 2 deg is needed. I jump from Telrad to 41mm Panoptic giving 1.6 deg on my Newt and yearn for 2 deg but focal length of telescope doesn’t allow it. Same eyepiece on my TV-101 and I get 4.9 deg of flat field! Best for Sagittarius region.

I typically then jump to 20mm Type 5 Nagler and this is a very nice focal length for both 1640 focal length and 540mm focal length giving approx 1 deg and 3 deg respectively. Yes a 21mm Ethos would be fantastic here giving me 25% more true field.

Try Eta Carina at 2 deg with O-III filter. Wow! Veil nebula too requires low power and of course Pleiades is best at low power wide field over 2 deg. As a 30x /2 deg. finder though is what a 40mm would be best for but like I said in my previous post a 30mm would complement it. Dark skies are better for larger exit pupils to keep the background darker.
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Old 09-03-2021, 11:05 PM
mr2ns
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Responses:
-I have a D-200mm and F=1200mm
-Im 37 and theres a little light polution.

@astro744
What are your recommendations?
What size eyepieces - 2inch on 1.25?
Are you recommending 1.25 30mm and a 3x 1.25 barlow?

Like @Allan_L I see the same with my scope. So all I need is the T-ring of ebay.

@gregbradley If 7.5 to 10mm are for planets, what is the 20-25mm suited for? Is this 1.25 or 2inch eye pieces?

hmmm the APM price tag is over budget, but with what I have, will two budget additional eyepieces make a significant difference or will something like that be a better investment to enjoy?
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Old 10-03-2021, 02:38 AM
astro744
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The 30 and 40mm I am suggesting are both 2”. The Superview have a larger apparent field than your current 1.25” Plossl eyepieces and as they are 2” will both give a larger true field than anything you currently have. E.g. the 30mm 2” in 68 eg apparent field will likely have a field stop diameter of around 33mm whereas the maximum a 32mm 1.25” will have us 27mm. It is the field stop diameter which is limited by barrel size that determines true field which is then also a function of telescope focal length.

True field of view (deg) = Field stop diameter (mm) x 57.3 / focal length of telescope (mm)

E.g. 27mm FSD, f.l.=1200mm
(Note 24mm/68 deg, 32mm/50 deg, 40mm/43 deg all have 27mm FSD giving same true field at different magnification all in 1.25”)

TFOV = 27x57.3/1200 = 1.3 deg.

E.g. 33mm FSD, f.l.=1200mm
(30mm/68 deg Superview in 2” only)

TFOV = 33x57.3/1200 = 1.6 deg.

E.g. 43mm FSD, f.l.=1200mm
(42mm/65 deg Superview in 2” only). (Note, the maximum FSD in 2” is 46mm. This is available from Tele Vue in 41mm/68 deg Panoptic and 55mm/50 deg Plossl, both 2”). The 42mm/65 deg Superview FSD is likely a little less at perhaps 43-44mm. Tele Vue state the FSD for all their eyepieces but many other manufacturers don’t). 43mm is an educated guess.

TFOV = 43x57.3/1200 = 2.1 deg.

Your telescope is f6 (1200/200) so exit pupil for a 42mm eyepiece is 42/6=7mm. This is your low power limit before you begin wasting light as typically your eye will open to 7mm. This is not a hard and fast rule and slightly greater exit pupil to gain true field under dark (or even suburban) skies can be beneficial. The magnification is 1200/42=28.

For a 30mm, exit pupil = 5mm, mag=40. Thus will give you a slightly darker background and less true field than the 42mm in 2” but more true field than the 32mm Plossl or 40mm Plossl or 24mm Panoptic in 1.25”.

I am suggesting one or both of the 42mm and/or 30mm Superview to complement your current eyepiece set. If you like what you see in the Superview then I am suggesting you add the 20mm and 15mm to your collection.you will then have all 65-68 deg eyepieces.

I do not recommend Barlowing anything over 30mm as eye relief is extended a little to far. (A Powermate corrects for this but a Barlow does not). I know a 2x 2” Barlow would give you the 20 (21)mm and 15mm as would separate 20mm and 15mm eyepieces and whilst you may get away with it with Barlowing the 30mm you will find it a problem with the 42mm.

If you feel your current eyepiece set could give better views then I suggest you slowly replace (as budget allows) each focal length with Tele Vue equivalent Plossls up to say 25mm and complement these with a 2x and 3x Barlow (1.25”) to give you some quality high powers. This will also complement any 2” eyepiece you buy in 30mm and over focal lengths. If you get one Superview first and like what you see in terms of apparent field of view and prefer that to a Plossl then don’t go down the Plossl path and simply get the 15mm and 20mm 1.25” Superview and a 2x and 3x Barlow. (Recommend Tele Vue Barlow but the GSO 2x and 3x are quite good; skip any ‘Shorty’ type Barlow). This will then give you effectively 5, 6.7, 7.5, 10, 15, 20mm in 1.25” all 65-68 deg apparent field and 30, 42mm in 2” also in 65-68 deg apparent field.

Best to try one Superview before you invest in all.

A third option which will give you a single but quality eyepiece that will perform well on any telescope you are ever likely to own is to get a used Tele Vue 24mm Panoptic. These are sometimes on sale for about $350 used on this forum. This will give you the same true field as a 32mm or 40mm Plossl but at higher power. At this stage in your hobby I would consider the Superview eyepieces but this is only a suggestion and not a recommendation based on your budget and the fact that I only have personal experience with the 15mm Superview on a short refractor.

Note any view you get will only be as good as the weakest link. Check collimation and observe when seeing is good and position your telescope so advise not to look over any local sources of heat. Mushy views are often seeing related or badly mis-collimator telescopes.
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Old 10-03-2021, 08:53 AM
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Originally Posted by mr2ns View Post
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Like @Allan_L I see the same with my scope. So all I need is the T-ring of ebay.
I got mine from a camera shop as you need to get the one specific to your particular camera, but I see you can get them on ebay also if you know what you need
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Old 10-03-2021, 07:36 PM
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@gregbradley If 7.5 to 10mm are for planets, what is the 20-25mm suited for? Is this 1.25 or 2inch eye pieces?

hmmm the APM price tag is over budget, but with what I have, will two budget additional eyepieces make a significant difference or will something like that be a better investment to enjoy?[/QUOTE]

A Bintel Barlow now gives any eyepiece 2 focal lengths. So that would be a recommendation. I got their 2 inch one for $89 and its very good, slightly better than the APM 2 inch barlow I got as well.

I found 17.5mm a nice comfortable and wide view at 819mm F6. SO allowing for the longer focal length that becomes 20-25mm.

The Dual ED 25mm I have is quite good and is only $89 on ebay.
Its not Televue, Baader or APM good but its a decent eyepiece given the low cost.

As I mentioned the TMB Planetary 2 is only $53 on Ebay and if you got the 9mm it would be a great lunar and planetary and DSO on a good night eyepiece. Way better performance than the $53 price tag would have you expect.

Celestron, Meade, Orion, GSO all have their budget offerings. Best to check out reviews by googling the brand and read what owners have to say about them.

I also got an SvBony 8-24mm zoom off ebay for about $125. Its pretty good. Again not the best but very flexible and I note many visual guys list a zoom as their favourite eyepiece. The Baader Hyperion 8-24 is usually regarded as the best. Its around $389 though. Quality costs but there are bargains.

Edmunds Optics RKE 28mm often comes up on all time 10 favourite eyepieces lists. Its only about AUD$163 shipped from Edmunds Optics Singapore.

https://www.edmundoptics.com.au/f/ed...epieces/12484/

I just ordered a 2nd one for use in a binoviewer.

Greg.
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  #12  
Old 11-03-2021, 10:46 AM
JA
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And I thought lenses were a headache to choose between .....

Best
JA
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Old 11-03-2021, 11:48 AM
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Quote:
Originally Posted by gregbradley View Post
@gregbradley If 7.5 to 10mm are for planets, what is the 20-25mm suited for? Is this 1.25 or 2inch eye pieces?

hmmm the APM price tag is over budget, but with what I have, will two budget additional eyepieces make a significant difference or will something like that be a better investment to enjoy?
I think one 20mm APM XWA ($490 or so) and a 2 inch Bintel barlow ($89)
gives you an effective 10 and 20mm. The barlow also helps correct the stars at the edge of the field of view. I would prefer that as its a wow eyepiece rather than 2 medium quality eyepieces that will be good but not wow.

Greg.

A Bintel Barlow now gives any eyepiece 2 focal lengths. So that would be a recommendation. I got their 2 inch one for $89 and its very good, slightly better than the APM 2 inch barlow I got as well.

I found 17.5mm a nice comfortable and wide view at 819mm F6. SO allowing for the longer focal length that becomes 20-25mm.

The Dual ED 25mm I have is quite good and is only $89 on ebay.
Its not Televue, Baader or APM good but its a decent eyepiece given the low cost.

As I mentioned the TMB Planetary 2 is only $53 on Ebay and if you got the 9mm it would be a great lunar and planetary and DSO on a good night eyepiece. Way better performance than the $53 price tag would have you expect.

Celestron, Meade, Orion, GSO all have their budget offerings. Best to check out reviews by googling the brand and read what owners have to say about them.

I also got an SvBony 8-24mm zoom off ebay for about $125. Its pretty good. Again not the best but very flexible and I note many visual guys list a zoom as their favourite eyepiece. The Baader Hyperion 8-24 is usually regarded as the best. Its around $389 though. Quality costs but there are bargains.

Edmunds Optics RKE 28mm often comes up on all time 10 favourite eyepieces lists. Its only about AUD$163 shipped from Edmunds Optics Singapore.

https://www.edmundoptics.com.au/f/ed...epieces/12484/

I just ordered a 2nd one for use in a binoviewer.

Greg.[/QUOTE]
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  #14  
Old 11-03-2021, 11:49 AM
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Originally Posted by JA View Post
And I thought lenses were a headache to choose between .....

Best
JA
Hehehe, Yes its quite a world of its own.

Greg.
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Old 11-03-2021, 08:42 PM
Hemi
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Quote:
Originally Posted by JA View Post
And I thought lenses were a headache to choose between .....

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JA
Not as many lenses to choose from as EP’s, thankfully.

This is a nice website...
https://eyepieceplanner.com/#/
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