EP Advice

[wibblefish]

 Howdy,

Ive been lucky enough to get some pennies towards new scope accessories so was hoping you kind people would be able to provide some advice if what I was looking at would be suitable. My budget is up to £250 (seems odd to spend the price of the scope on EP!) though happy to not spend that much if its not worth it!

I currently have a 90/660 f7.3 short tube refractor with standard skywatcher super ma 25 and 10mm EP. I have found the 25 is fairly decent but the 10 is not so great for eye relief (targetting the moon). I wear glasses though I am happy not to use them at the scope (I cant with the 10mm but can just about with the 25).

I have been mostly targetting star clusters and some nebula type DSO. I would like to be able to go a little closer to the moon / other planets and maybe splitting some doubles but primarily I am looking for more wide field views as that seems to give me the wow factor at present. I am not sure how wide I can reasonably go with this scope as it does seem to go a bit less sharp or something at the edges with the 25mm.

With that in mind my thoughts are to get something like the following:

- 2.25 baader classic q barlow

- 12mm bst starguider 

-  24mm es 68

I figure the bst will give me a good view for planets and barlow to near the max for the scope while providing more eye relief than the 10mm I currently have.

Then I was torn with the ES in terms of spend as it seems a lot for a single lens but it seems like the widest of the available options though streching on the budget. I did wonder wether to get a couple of smaller 60 lenses from BST to cover more range instead (ie a 24 and an 18) or maybe Vixen npl at 30mm instead.

Another option might be going for a cheaper set of plossl for more range or maybe even a zoom but Im not sure what to look at there. Again not sure if one or two good quality (and maybe expensive EP are better than lots of cheaper ones). Bewildered by the amount of choice!

Any suggestions or advice welcome! 

 

Edited January 1, 2021 by wibblefish

[azrabella]

A Happy New Year to you.

I can recommend the BST's. I think they are very good value and with your particular scope the 25mm BST would give you 26x - great low power, wide vista views. Followed by a 12mm @ 55x and an 8mm yielding approximately 82x - all with excellent eye relief and all with a 60 degree field of view. If you want to go wider field of view then the Skywatcher/OVL Nirvana eyepiece range, while not as extensive as the BST's (16, 7 and 4mm), are very good indeed. Couple them with a good quality Barlow  and you have a nice range of focal lengths at reasonable cost. All these are better than standard plossls by some margin.

[rwilkey]

Hi Wibblefish, the BST StarGuiders recommended above are excellent all-rounders with good eye relief.  Avoid plossls as generally they have short eye-relief esp. the higher mags.  If you are thinking of Moon and splitting double stars I can think of nothing better than the William Optics SPL's, which have 20mm eye-relief.  The 12.5mm for the Moon (52x) and the 6mm for medium (separation) double stars (110x).  These will be enough to get you started on your most desired targets.  The SPL's can be found here: https://www.firstlightoptics.com/william-optics-eyepieces/william-optics-spl-eyepiece.html

Good luck and clear skies!

Edited January 1, 2021 by rwilkey

[rwilkey]

I have just realised, the SPL's are currently out of stock at FLO, try elsewhere or in particular the second hand market, here: https://www.astrobuysell.com/uk/

[wibblefish]

@azrabella thanks I have looked at the BST range and it seems good in terms of value and well recommended here but seem to ha read the 25 is not so good somewhere. Ill have a play with the nirvana etc in fov calcs cheers for the suggestions.

@rwilkey I havent looked at that brand, will have a look now, appreciated! Bit dubious of buying second hand kit though 🤔

Edited January 1, 2021 by wibblefish

[Spile]

I have just updated my "default" 10 and 25mm EPs. Like you I found the 10mm lacking.

After scouring the forums, the one that kept getting good reviews and recommendations in terms of sweet spot (optics/cost) was the Baader Hyperion IV Zoom, and that is what I chose.

It was bundled with a matching Barlow at a special price so I went for that. It is BIG but mounted on 2" adapter it is secure though a little daunting!

I now have a handy range of focal lengths (3.6 - 24mm) and a magnification range from 20X to 338X and the only changing I need to make are to insert or remove the Barlow.

Checking out Saturn and Jupiter last night, the difference was considerable, features were more prominent and better defined. To be expected for something that costs almost as much as my telescope!

All in all, I am very happy with the decision.   

 

[rwilkey]

11 minutes ago, Spile said:

I have just updated my "default" 10 and 25mm EPs. Like you I found the 10mm lacking.

After scouring the forums, the one that kept getting good reviews and recommendations in terms of sweet spot (optics/cost) was the Baader Hyperion IV Zoom, and that is what I chose.

It was bundled with a matching Barlow at a special price so I went for that. It is BIG but mounted on 2" adapter it is secure though a little daunting!

I now have a handy range of focal lengths (3.6 - 24mm) and a magnification range from 20X to 338X and the only changing I need to make are to insert or remove the Barlow.

Checking out Saturn and Jupiter last night, the difference was considerable, features were more prominent and better defined. To be expected for something that costs almost as much as my telescope!

All in all, I am very happy with the decision.   

 

Might be a bit heavy or cumbersome in a short tube refractor, though good for a 200P Newt?

[KP82]

24mm 68 degree gives the widest possible fov for the 1.25" format and ES68 24 is a very good performer among all the 24/68 eyepieces, possibly only beaten by TV Panoptic 24. A 30mm 1.25" plossl will not be wider than this, but will produce less magnification and bigger exit pupil which could result in a brighter background depending on the level of your local light pollution.

The BST 12mm produces very good views for its price. I had one before and loved it. The BST 25mm is the weakest of all the starguiders. I'd definitely choose ES68 24 over it unless I was on a low budget.

Edited January 1, 2021 by KP82

[Zermelo]

On 01/01/2021 at 10:54, wibblefish said:

seem to ha read the 25 is not so good somewhere.

It was possibly here. There are reports of noticeable edge astigmatism on the 25mm in fast scopes (the majority of the BST range are adjudged to perform well down to F/5), though your scope may not be affected at F/7.3.  The Vixen NPLs are Plossls, but Plossl eye relief increases with focal length and the 30mm has a decent 24mm ER.  The NPL 30mm has a 50 degree AFOV versus the 60 degree (nominal) on the BST, but the longer focal length will give you the same true FOV of 2.3 degrees. But as @KP82 says, it will give a wider exit pupil, which could make it a bit less effective for locating DSOs than the shorter EPs where there is background light pollution.

 

Edited January 4, 2021 by Zermelo
removed comment about non-existence of NPL 25mm; it does exist, but FLO don't list it for some reason

[wibblefish]

@Spile  I think thats the one I have seen recommendations for. I was going to say its quite large but then I think its smaller and lighter than the ES68 I was thinking of. Food for thought cheers

@KP82 @Zermelo yeah I think thats why I had thought of something else as the BST seem to be particularly good toward the higher magnifications so I figured barlow one to give two options for close work. I will do the exit pupil calcs on the vixen vs the es68 I think it was about 3.2 vs 4.1 or something. I think I am a little concerned the ES68 is a lot of cost for a single EP but  it does seem to get good reviews plus alot of people seemed to recommend buying some quality  rather than scattering lots of lower costs. Hohum decisions!

Edited January 1, 2021 by wibblefish

[PEMS]

2 hours ago, wibblefish said:

@azrabella thanks I have looked at the BST range and it seems good in terms of value and well recommended here but seem to ha read the 25 is not so good somewhere. Ill have a play with the nirvana etc in fov calcs cheers for the suggestions.

@rwilkey I havent looked at that brand, will have a look now, appreciated! Bit dubious of buying second hand kit though 🤔

I would not worry overly about the performance of the 25mm, it performs well.

At times you will likely read that someone somewhere thinks each of the individual focal lengths are "the weakest". Not sure why people have to try and identify "the worst" in their opinion, seems so pointless. I suppose the rather simple answer is they all perform above their price point.

The ES 24/68 will deliever the widest field however be aware the additional width is minimal. Reality is a 25mm BST, 30mm plossl and ES24/68 will all be very close to each other. Even the ES 30mm 52 degree will be almost identical. The spread is likely 0.1 degrees and that is edge to edge.

[Zermelo]

1 hour ago, wibblefish said:

@Spile  I think thats the one I have seen recommendations for. I was going to say its quite large but then I think its smaller and lighter than the ES68 I was thinking of. Food for thought cheers

@KP82 @Zermelo yeah I think thats why I had thought of something else as the BST seem to be particularly good toward the higher magnifications so I figured barlow one to give two options for close work. I will do the exit pupil calcs on the vixen vs the es68 I think it was about 3.2 vs 4.1 or something. I think I am a little concerned the ES68 is a lot of cost for a single EP but  it does seem to get good reviews plus alot of people seemed to recommend buying some quality  rather than scattering lots of lower costs. Hohum decisions!

I've worked myself to a deadlock thinking about this for a while too, i.e. wanting to upgrade my longest EP to a better "locator" with the best combination of sharpness, TFOV and exit pupil within my budget (<~£100). If the BST 25mm had been as universally popular as the rest of the range I'd probably have gone for that straight off. The 30mm NPL gives an exit pupil that's a bit on the large size with my F/5 scope. And then I saw the Explore Scientific models and wondered whether to save up ...

Edited January 1, 2021 by Zermelo

[Pixies]

If you are going to barlow a 24mm eyepiece (albeit a x2.25 one). It'll effectively be a 10.7mm EP.

In your scope:

24mm = 50x magnification

12mm = 100x magnification

barlowed 24mm = 120x

barlowed 12mm = 200x

 

which isn't the best spread of magnifications, IMHO. Many would suggest a spread using a common multiplier, say 1.4:

50 = 24mm ES (£138)

70 = 17mm ( 18mm BST = £42 with bulk discoount)

100 = 12mm  ( 12mm BST = £42 with bulk discoount)

140 = barlowed 17mm (  Baader Classic Q - £39)

200 = barlowed 12mm

= £261

 

This would be an evenly spread range from a good wide-field (x50) up to the max x200 for planetary viewing on very good nights / double star splitting..

Or you could keep the ES and Barlow, and replace the BSTs with the smaller OVL Hyperflex zoom (£69):

https://www.firstlightoptics.com/ovl-eyepieces/hyperflex-72mm-215mm-eyepiece.html

which would be £246

Edited January 1, 2021 by Pixies

[Mr Spock]

I think you'd be happy with a range of BSTs. They offer good performance while still being relatively inexpensive. You can get better, but the cost jumps rapidly.

[wibblefish]

@PEMS I have run quite a few comparisons with a fov tool and the es68 is the widest and by a margin but it is probably fractional gains at that level I guess as you say cheers!

@Zermelo yes I am gradually working myself to indecision 

@Pixies interesting I did actually think that an 18 would be a solid choice from calcs but was unsure wether itd be redundant with overlapping EP at the wide end. 
 

@Mr Spock yesh I did originally think several BST 12/18/25 plus barlow might be good value vs quality before diving into the ES68 rabbit hole after looking at celstron Ex-Cels  

 

 

 

Edited January 1, 2021 by wibblefish

[wibblefish]

I think its down to the suggestion that @Pixies made of the es68 24mm, baader barlow, 18mm bst, 12mm bst or stick with a full bst lineup short barlow, 25, 18, 12 for the current discount. The price difference is mostly in the es68 of about £100 which is significant. I am starting to lean towards that as @Mr Spock and @PEMS have suggested perhaps there isn’t going to be £100 of difference to my eyes at least for the moment and Im less concerned about spending that than dropping the majority on one EP and getting it wrong! 😎

Thank you all for the input plenty to consider! 

 

Edited January 1, 2021 by wibblefish

[Pixies]

Either sets will be good - although don't write off a zoom. However, a zoom had the disadvantage that at how power, the FOV reduces, so it's not suitable a a wide-angle finder EP.

With whatever you choose, it's just the start of your EP purchasing journey! You can change your mind later and if you want to replace anything, the resale of good EPs isn't too bad.

[Spile]

6 hours ago, rwilkey said:

6 hours ago, Spile said:

 

Might be a bit heavy or cumbersome in a short tube refractor, though good for a 200P Newt?

No problem with the 200P. Note that I have the 2” extension fitted in the shot. I tried 1.25” barrels and no problem, I just preferred the “security” I felt the 2” gave me. The convenience is a big plus for me and the range of magnifications especially when paired with the Barlow.