8" Edge HD - Wider FOV ?

[BRUN]

ive switched from a dob to an SCT and although ive barely used it one thing ive noticed is that the FOV is a lot smaller on the SCT

ive just done some very brief reading and will something like this give me a permanent wider FOV ?

https://www.firstlightoptics.com/edge-hd-series/celestron-reducer-lens-7x-edgehd-800.html

anything cheaper that would achieve similar ?

[MBJ]

you can definitely get cheaper reducers for celestron 8" sct,s as i have one.

the standard f6.3 celestron reducer should fit and a fraction of the price.

https://www.firstlightoptics.com/reducersflatteners/celestron-f63-focal-reducer.html

 

[souls33k3r]

25 minutes ago, BRUN said:

ive switched from a dob to an SCT and although ive barely used it one thing ive noticed is that the FOV is a lot smaller on the SCT

ive just done some very brief reading and will something like this give me a permanent wider FOV ?

https://www.firstlightoptics.com/edge-hd-series/celestron-reducer-lens-7x-edgehd-800.html

anything cheaper that would achieve similar ?

There is a  Optec Lepus 0.62x reducer but people who've used it have only complained. Unfortunately you're only chance to reduce the scope is using the one you mentioned in the link.

10 minutes ago, MBJ said:

you can definitely get cheaper reducers for celestron 8" sct,s as i have one.

the standard f6.3 celestron reducer should fit and a fraction of the price.

https://www.firstlightoptics.com/reducersflatteners/celestron-f63-focal-reducer.html

 

Sorry but the reducer you mention @MBJ will only work with NON-EdgeHD version. 

Hope this helps

[John]

Cheaper to buy a 2nd hand 8" dob for wide field use though ?

The SCT was bound to deliver a narrower field of view when you think about it - F/10 2000mm focal length v's F/5.9 1200mm focal length

If you go for a reducer for your SCT for visual check that it will work with 2" eyepieces - some are intended for 1.25".

[MBJ]

3 minutes ago, souls33k3r said:

There is a  Optec Lepus 0.62x reducer but people who've used it have only complained. Unfortunately you're only chance to reduce the scope is using the one you mentioned in the link.

Sorry but the reducer you mention @MBJ will only work with NON-EdgeHD version. It only works with the normal 8" SCT

Hope this helps

yeah just read up on that. my bad lol 

 

the other solution is to buy one that screws onto the eyepiece.

[souls33k3r]

Just now, MBJ said:

yeah just read up on that. my bad lol 

 

the other solution is to buy one that screws onto the eyepiece.

lol it's all good mate

[MBJ]

6 minutes ago, BRUN said:

anyone selling one ? lol

depending on your eyepice collection wether 2" or 1 25" you can buy a 0.5 reducer that screws onto the eyepiece

[Stu]

I think the best option is to go for a long focal length eyepiece such as a 42mm 65 degree Vixen LVW or similar. You end up being limited by the aperture of the baffle tube but I used one of these with good success. Ultimately an SCT is not a widefield instrument so it's best to use it for its strengths rather than continually trying to overcome the long focal length.

[Cosmic Geoff]

You could fit a 2" visual back, a 2" diagonal and a 2" eyepiece with a long focal length e.g. 37mm, if you don't have these already.  These would give a wider field of view, and should work out cheaper than the eye-watering price of the 0.7 reducer.

[BRUN]

does this adapter fit straight onto the back of the scope ?

[Cosmic Geoff]

I don't know what you have on the back of your Edge HD, but if it has a 1.25" visual back I assume you just unscrew it and screw on a 2" visual back.  That's what's supposed to happen with my C8. On mine the relevant part has 'Visual Back 1 1/4"' stenciled on it in white.

If your Edge HD came with a 2" visual back (which AFAIK some of them do) you're already there.

[BRUN]

yea i do have a 2" back IIRC

[alanjgreen]

On 13/10/2017 at 08:54, BRUN said:

yea i do have a 2" back IIRC

If you have a 2" visual back then you will be using a 2" diagonal.

The celestron standard stuff is 1.25" and the diagonal is also 1.25"

When I had an 8" SCT then to get a wider field, I went the 2" visual back route and then bought a 2" diagonal and used a 22mm 82 degree eyepiece (2" Nagler) to great effect. My favourite widefield eyepiece on the SCT was the 41mm panoptic (2" of course). When I moved to the C11 then the diagonal came with me and I just needed to buy the 3.25" visual back (that the C11 takes).

Here are some 2" visual back links (to make it clear what we are talking about - you just unscrew the standard celestron one and these replacements just screw back onto the same thread but the "hole" is now 2" rather than just 1.25"). Keep the celestron stuff in case you sell the scope then you can put it back to its original state. You can get more back selling the non standard stuff as separates rather then bundling it in with the scope.

https://www.firstlightoptics.com/adapters/baader-click-lock-2-for-celestron-meade-sct.html

https://www.firstlightoptics.com/adapters/baader-sct-to-2-inch-adapter.html

You can also buy 2" diagonals that screw direct to the scope, but i would not recommend these as the main benefit of the of separate diagonal is that you can screw your 2" filters to the diagonal meaning that you can swap eyepieces without need to swap the filter all the time.

Here are some of those:

https://www.firstlightoptics.com/diagonals/william-optics-sct-adapter-for-2-diagonals.html

https://www.firstlightoptics.com/diagonals/william-optics-2-dielectric-diagonal.html

Keep your eye on the 2nd hand section. The sct visual backs come up quite often and as they contain no glass are pretty much safe as houses in the post!

As far as 2" eyepieces go, then I would buy something like this, if I were doing it again now... starting with the 30mm

https://www.firstlightoptics.com/explore-scientific-eyepieces/explore-scientific-82-degree-series-eyepieces.html

 

Alan

 

[John]

I think the quandary with an 8" (say) SCT is, do you invest in the 2" visual back / 2" diagonal / 2" wide field, long focal length eyepiece / 2" filter to fit it which means investing around £300 in the scope (more if you go for premium items) to go from a max true field of view of .88 degrees (1.25 max field eyepiece) to a 1.36 degree true field (2" max field eyepiece) ? or do you invest a similar amount in a faster scope to do the wide field job and get the potential of 2,4 or eve 4 degrees of true field

 

 

[Cosmic Geoff]

24 minutes ago, John said:

I think the quandary with an 8" (say) SCT is, do you invest in the 2" visual back / 2" diagonal / 2" wide field, long focal length eyepiece / 2" filter to fit it which means investing around £300 in the scope (more if you go for premium items) to go from a max true field of view of .88 degrees (1.25 max field eyepiece) to a 1.36 degree true field (2" max field eyepiece) ? or do you invest a similar amount in a faster scope to do the wide field job and get the potential of 2,4 or eve 4 degrees of true field

£300? Really? When I priced up a 2" visual back, 2" diagonal and 2" eyepiece for my C8, I arrived at a figure of around £100 (minimum).  As I already had wide field telescopes I decided not to bother.

[John]

I've assumed £40 for the 2" visual back, £100 for a 2" diagonal, £100 for a decent long FL wide field eyepiece and £60 for a decent UHC filter. You can spend less or much more of course.

 

[ollypenrice]

I certainly wouldn't bother with the reducer since you'd reach the limits of the baffle tube in an optically purer way by going for the 2 inch back and the ultra wide FOV 2 inch eyepiece. 

Olly

[Stu]

3 hours ago, John said:

I think the quandary with an 8" (say) SCT is, do you invest in the 2" visual back / 2" diagonal / 2" wide field, long focal length eyepiece / 2" filter to fit it which means investing around £300 in the scope (more if you go for premium items) to go from a max true field of view of .88 degrees (1.25 max field eyepiece) to a 1.36 degree true field (2" max field eyepiece) ? or do you invest a similar amount in a faster scope to do the wide field job and get the potential of 2,4 or eve 4 degrees of true field

 

 

It's a tricky one John, but actually moving  from 0.88 to 1.36 degrees does make a number of objects more comfortable in the eyepiece so if you want to stick with one scope then in my view it is worth it. I think generally having a 2" back and diagonal is a good investment anyway, I just prefer the more secure connection which helps every with larger 1.25" eyepieces.

[BRUN]

4 hours ago, alanjgreen said:

 

https://www.firstlightoptics.com/adapters/baader-click-lock-2-for-celestron-meade-sct.html

 

Alan

 

i have this one on mine at the moment, and my diagonal is 2" (it can do both) but due to costs im on 1.25" EP's, but they are all ES 68/82 degree

[alanjgreen]

7 minutes ago, BRUN said:

i have this one on mine at the moment, any my diagonal is 2" (it can do both) but due to costs im on 1.25" EP's

Sounds like all you need is a nice 30mm+ 2inch eyepiece in that case.

You can keep an eye on second hand if you want to save 30% of new price!

 

[BRUN]

would you suggest a 2" set, or just the larger ones in 2" ?

im looking for a 56mm Meade atm actually as a finder EP

[alanjgreen]

24 minutes ago, BRUN said:

would you suggest a 2" set, or just the larger ones in 2" ?

im looking for a 56mm Meade atm actually as a finder EP

No need for a set!

Why do you need a finder EP if you are getting a starsense camera? - it will find it for you!

I had a 41mm panoptic which was great for the Veil and other "wide" targets (you wont get them all in but you get the max possible FOV) - 41mm panoptic is the widest possible 2" view. The 56mm Meade only has 50 degree FOV so dont get fooled by the big mm quotes.

- you need to note the focal length (mm) AND the FOV of each eyepiece.

- a small FOV combined with a big focal length just means that you see the same but with less magnification

Your best bet is "30mm with 82 degrees" OR "40mm with 70 degrees" this will maintain decent magnification with no actual loss of FOV.

 

fyi, I had a 2" 41mm 68degree Panoptic and then my next longest eyepiece was a 2" 22mm 82degree Nagler. Two 2" EPs were sufficient. I then had 17, 14, 12 & 10mm in 1.25" size.

If you buy 2" filters and put them onto the diagonal (scope side will have a filter thread) then it does not matter if you have a mix of 2" and 1.25" EPs

 

[BRUN]

thanks for those numbers, all this is new to me really so i need all the help i can get

[alanjgreen]

22 minutes ago, BRUN said:

thanks for those numbers, all this is new to me really so i need all the help i can get

if you download "sky safari" then you can add "equipment" and enter eyepiece focal length/fov combinations. You also enter your scope details (focal length) then it can project "circles" onto the display so you can see which will get the widest actual field of view

Looks like FLO have a sale on some skywatcher 70 degree EPs

https://www.firstlightoptics.com/clearance/sky-watcher-swa-70-eyepieces.html

there is a 32mm at the bottom that should work well in an SCT (they are forgiving on eyepieces due to being slow f/10) - of course if you use a reducer then you will increase the speed and then it may be a bit more challenging for the cheaper EPs!

Always have a read for reviews of any EP you decide BEFORE rushing into buy mode

 

 

[alanjgreen]

31 minutes ago, BRUN said:

thanks for those numbers, all this is new to me really so i need all the help i can get

More good info to be found in here

 

And a few votes here for a 40mm maxvision from FLO

 

https://www.firstlightoptics.com/explore-scientific-eyepieces/explore-scientific-68-degree-maxvision-eyepieces.html