Advice on a picking a refractor

[Ratlet]

I'm currently very much satisfied with my optical arsenal of a 130pds and a 10" Stellalyra dob.  They do the business and gobble the photons, however part of the joy of the hobby for me has been building my experience and figuring out what I like (and the forum has been very helpful with my journey in eyepieces).

With that in mind, I feel it is approaching time to join the dark side and get a refractor.

Primarily it'll be used for visual, however I'd like something I can use for astrophotography if possible so some form of ed scope.

In an ideal universe I'd like to be able to use it with my current mounts (gem28, azgti and az5).

Currently budgeting about £900.  

My current location is bortle 4/5 skies.

And that dear friends is where I fall down.  Part of me thinks that some form of grab and go setup would be sensible given what I've got and the guys at Actual Astronomy sing the praises of the small aperture doublet.  Something like the stellamira 80mm, or a William optics 73mm.  I feel the short focal length would be complimentary to my current kit.

The other part of me thinks a larger more well rounded scope would be a better option.  I'll be honest here that the reports on the Starfield 102mm are what is calling me down this road and it's basically the only horse in the larger aperture race at the moment.

Given the focal length of this I feel the statfield would be less complimentary but would be a more well rounded option and be somewhat similar to the 130pds and I think (could be wrong) that the clear aperture would be pretty close to the 130pds once you account for the secondary and I know I'm happy with its performance on pretty much everything.  A safer option perhaps?

Does anyone have any thoughts?  Am I likely to be able to mount a Starfield on my current kit?  Should I try out smaller aperture observing?  You guys haven't failed me yet so I'm keen for some opinions.

[ED Splitter]

Buy the 4” apo of your choosing. Great grab and go size, cools quickly, will serve you well under those skies. You buy the 80mm and you will forever be thinking about the 4” you never bought. 
Is the budget entirely for the scope or are accessories to be  included? I’m sure second hand shipping accessory wise will assist in budget restrictions.  

[Elp]

Refractors do provide the crispest sharpest views, I do feel however compared to your other scopes one would be aperture limited somewhat so the views likely dimmer maybe. For visual there are a lot of options, I had an acro one early on but couldn't compare to the apo I bought after it (WO Z61), scopes have come and gone but this one continues to be the workhorse. Even viewing Saturn as a realistic 1-2mm dot and ring was fantastically sharp, Jupiter has provided me the best through it too (I've also seen it through a 130pds and C6). For AP I really can't see how getting a significantly more expensive scope will benefit after the z61 (other than one of a larger aperture and FL for speed and detail). I also use a gem28 and azgti, this scope works very well on them. I am looking to get a larger aperture but the weight is an issue for the azgti for AP so am a little limited, for visual you'll have more options and can possible go up to a 90/100mm if your tripod is sturdy, with the other two mounts you have you're not really limited.

The starfield does look interesting as does the stellamira, there's also the scopetech. The new founder optics might be in reach too. I'm a little wary of manufacturers who don't specify the glass type though, for imaging FPL53 or equivalent glass really does make a difference, even for visual, if it's not too much of a priority most ED lenses will do.

Edited June 5, 2023 by Elp

[mikeDnight]

I'd go for the Starfield 102ED in a hear beat. The Starfield will give you both rich, wide, low power vistas, while also offering piercingly sharp, clean, high power views of double stars. The Planets and Moon will be crisp with great contrast and definition. You may even be pleasantly surprised at how bright many deep sky objects look through the 102ED.  A 4" refractor can be an awesome companion as it is easy to set up, quick to reach thermal equilibrium, and is a great all round performer. It would also give pleasing images!

[Ratlet]

15 minutes ago, mikeDnight said:

I'd go for the Starfield 102ED in a hear beat. The Starfield will give you both rich, wide, low power vistas, while also offering piercingly sharp, clean, high power views of double stars. The Planets and Moon will be crisp with great contrast and definition. You may even be pleasantly surprised at how bright many deep sky objects look through the 102ED.  A 4" refractor can be an awesome companion as it is easy to set up, quick to reach thermal equilibrium, and is a great all round performer. It would also give pleasing images!

My working theory at the moment is that the views through the 102 wil be only slightly dimmer than the 130pds due to the secondary cutting down some of the light in the newt.  I'm very satisfied by its performance on DSO.

A boost in contrast on planets would be great as the 130pds was a bit poor on contrast (although this could be solved with a filter).  

[Mr Spock]

As a former Starfield owner I can say for certain you won't get better value for money. Optics are very, very close to the best there is and I'd say you'd find the difference between the Starfield and the 130 to be more startling than you realise.

For AP it has a matching 0.8 reducer/flattener which will give you 571mm f5.6. If you have a small chip (4/3 or less) you can get a 0.6 reducer for 428mm f4.2. 

Oh, and did I mention it's a thing of beauty...

[Coco]

StellaMira 80mm ED f/10 would be a killer on the Sun, doubles, planets and the Moon.

Lost count how many times I've had the StellaMira 80mm ED f/10 or  Starfield in my shopping cart 😁

[Ratlet]

8 hours ago, Mr Spock said:

As a former Starfield owner I can say for certain you won't get better value for money. Optics are very, very close to the best there is and I'd say you'd find the difference between the Starfield and the 130 to be more startling than you realise.

For AP it has a matching 0.8 reducer/flattener which will give you 571mm f5.6. If you have a small chip (4/3 or less) you can get a 0.6 reducer for 428mm f4.2. 

Oh, and did I mention it's a thing of beauty...

A moment of honesty from me here:  I hold you about 90% responsible for my interest in this scope.  Your observing reports and comparisons with this scope have been very informative.  You seem to find good synergy with a 4" Doublet and your 12" Dobsonian and I find myself with a similar restriction for setting up where the dob gets restricted views to the East and a bit of mobility is nice for grabbing those low flying targets, not to mention a good location nearby which give unobstructed 

It is a very attractive scope as well!

When you say the views will 'be more startling than you realise', could you elaborate?

I was not aware that there was a 0.6 focal reducer available.  That makes a very interesting option for imaging and also provides excellent synergy with my other gear (135mm, 200mm and 300mm vintage lenses).  I don't do a lot but that is partially because I don't have an optimised setup routine, although I've been working on that and I think I'm getting the kinks worked out.  That being said, given the choice between observing and imaging, the camera will be staying in the box!

In terms of accessories, I think I'll have enough to get going (they seem to accumulate in the hobby) but the only thing I'm really lacking is a diagonal.  I have a circle T prism but I suspect that this might not be optimal.

[bosun21]

I’m another overwhelming thumbs up for the Starfield 102. It’s a great 4” refractor that’s fantastic value and quality. The images are crisp and clear with good contrast. For me it’s a great scope to accompany my 12” dobsonian. I stupidly sold my first one but quickly replaced it when I missed it so much.

[Nik271]

I can make  a comparison between a 150mm F5 Newtonian I sold 2 years ago and a ED 102mm F7 Svbony refractor I currently have and use frequently (which is close but not quite as good as the Starfield due to using cheaper FL51 glass). They both had similar focal length 714 vs 750mm.

The Newtonian was very good quality and the images were brighter than the refractor. This is where the advantage of the Newtonian ends though. The star in the newt while  OK at very low mag started to show diffraction spikes and coma at the edge of the field. The Newt was cumbersome to mount and I found the position of the eyepiece uncomfortable. I was always worried about collimation and checking and tweaking it every few weeks. 

The refractor is a pleasure to use, only 4kg with rings attached. Up to 180x the image is CA free except on extremely bright objects (Venus, Sirius). It is ready to use right out of the box, I dont even use a finder only a RDF for rough alignment since a 32mm Panaview can give me 3 degree field of view in the scope.

Even though this is not my primary planetary scope (I prefer my 127 Skymax for high magnifications) it still gave very pleasing views of Jupiter and Saturn last summer. It can split tough doubles like Delta Cygni or  Iota Leonis with relative ease.

So in terms of versatiliy and ease of use a 100mm class ED refractor beats a Newt in my books. Under dark skies competing on dim DSO is the only place where a 6 inch Newt can pull ahead.

 

Edited June 6, 2023 by Nik271
typos

[Mr Spock]

8 minutes ago, Ratlet said:

When you say the views will 'be more startling than you realise', could you elaborate?

A good apo has a clarity, contrast, sharpness and detail a reflector can't match, especially one as small as 130mm. The 130 will seem like mush in comparison. Apos have a different way or rendering what you are looking at, from tight, clean airy disks to fine contrast and planetary detail. If you can get an eyepiece in the 3 - 3.5mm range then lunar and planetary views will be sharp and crisp. I used mine on the moon a lot, even leaving the 12" in the shed - except in excellent seeing of course.

On a good night a 200mm will be better, but the ability of the 4" to cut through average seeing would have me reaching for the 4" more often than not. You'll also find it better on deep sky than you expect - aperture is always the main consideration for faint fuzzies but apos have a clarity that really belies their size.

The 4" apo also opens up the world of solar observing. Add a wedge and it's as good as it gets.

The large dob/4" apo is a combination many people have; those two scopes have synergy. 

If I hadn't had a moment of lunacy and bought a Tak, I would have kept the Starfield for life. I still have moments of regret 

[Nik271]

PS. I recently acquired a 70mm ED F6 doublet to use as a solar scope. If you just want wide quick views this is also a good option. Only 2 kilos and can sit on a photo tripod, a real grab and go in one hand! The 100mm refractor will need  a mount of class at least AZ5, technicall still G&G but with both hands :-)

Edited June 6, 2023 by Nik271

[dweller25]

In my opinion a good 4” Refractor and a 10” Dob are the perfect combination.

If you buy the STARFIELD 102 F/7 ED DOUBLET 🙂 I suspect you will find you no longer need the 130PDS.

 

 

[WolfieGlos]

Another vote for the Starfield 102. I've had mine for about 6 weeks now, and it is a superb scope. Coupled with the adjustable 0.8 reducer to achieve backfocus, it performs flawlessly and backfocus was easily achieved. My stars are near perfect right into the corner with a DSLR. This would be slightly above your rough budget at roughly £1100, but worth it in my opinion.

It will be limited for larger targets (i.e. Andromeda, NA and Veil Nebula, etc), but mosaics can be considered instead. I did consider the Stellamira 110ED, but it was (and still is) out of stock.

My only other comparison is with my other scope, the Evostar 72ED. The performance of that with the SW flattener or Stellamira version, has put my off of skywatcher refractors in the Evostar range for good.

[Naughty Neal]

Starfield with the slightly better FPL53 glass is on my list to buy in the future, but by then I may miss the boat or something as good will be available.  

 Mr Spock aka Micheal has prety much shown it is a top scope . 

Edited June 6, 2023 by Naughty Neal

[M40]

Quick question for you Ratlet, how much do you like your 130pds? Because I'm going to side with dweller25 and say that you won't use it when you get a refractor with a similar fov and good glass 👌

[jjohnson3803]

I recently sold my AT102ED f7 (looks like a Starfield twin).  It gave very crisp views and was a nice aperture, but it was too big and bulky for my tastes.  Also, it did not do that well on my SkyWatcher AZ5.  It was ok, but was a bit beyond the limits of "good" IMO for the wiggles / damping time.  Others might have had better experiences with that combo, I don't know.

I do love my AT72ED.  Maybe a little small in aperture for really faint fuzzies, but it's become my most used scope.

And having said that, I think I'm going to sell my ST120 achro and get a ST102 achro for a little bigger cheap grab-n-go than my ST80.

If by chance a female companion questions the purchase / sale of multiple scopes, compare them to women's shoes - you need to buy and try  *many* styles and designers before you find ones you really love. 

 

 

 

[cajen2]

Yet another happy Starfield user (Mr Spock's old one). 

But nobody seems to have addressed your mounting question. I think it would be rather undermounted with the AZ5 or AZGTi, both of which have a 5kg limit. I weighed my Starfield at 5.3kg with all the trimmings added (even an EP), and while you could shave a few grams off that, it'd still be pushing those mounts pretty hard. I use a 6x30 finder and a 2" diagonal but changing those wouldn't make a huge difference. My mount is the AZGTiX, which has a 6kg one-side limit and a 10kg total limit and even that is only just enough.

[Paz]

I agree with the recommendation of a 4" refractor, and the 102mm f7 apo that gets a lot of mentions is a great option. I've had one of those for about 3 and a half years and its been my most used scope since I got it.

Two things I would highlight are mounting - mine is fine on a Skytee 2 and an EQ5, but is a bit vibey on a Porta 2. I have not used the mounts you mention but looking at them the azgti and az5 look like they would be a bit vibey, the gem 28 would be fine if as advertised it can handle up to 12.5kg. It depends on your sensitivity to vibes - I am very sensitive to vibes so I only use the Porta 2 if I have to.

..the other is complementarity if you have a number of scopes. I agree with the comments that it would compete directly with the 130pds and that other than light gathering on dim objects where the 130 wins by sheer horsepower the 4" refractor would be on a par or win on most other things. I would get a 4" refractor, sell the 130pds, and run with a 10" dob and 4" refractor - that is as good a combo as you can get. My main scopes are a 3" refractor for travel, a 4" refractor for grab and go and general purpose, and a 14" reflector for epic observing, they complement each other very well and don't compete with each other.

It is worth keeping in mind the limitations of 4" of aperture and that it is the combination of the quality of the views, ease of use, and versatility of the scope that make it a good prospect.

[RobertI]

I’d agree with most of the comments, and would heartily recommend the Starfield 102ED (or Altair Astro or TS equivalents). I agree that it is not really complementary to your 130PDS and is more like a replacement, assuming you prefer the refractor views (who doesn’t love those pinpoint stars and crisp planetary views?), but you will be able to make a direct comparison to understand the pros and cons of each. Obviously the 130PDS is not really optimized for visual with the larger secondary. My F7 102ED is also a little kinder to eyepieces than my F5 130 Heritage - my 21mm Hyperion is almost unusable in my 130 because of edge of field aberrations but is acceptable in the 102. I find the 102 is rock solid on my AZ4 and steel tripod, I’d assume the AZ5 is as solid, but may be wrong judging by some comments above. 

I still have a soft spot for Newts though, and would make some points in favour of the 130PDS (which you already know as you own one!):

• Newts are better for viewing overhead IMO as the the eyepiece position is better - if you have an EQ mount too, you access all those objects in the best part of the sky.
• The resolving power of the 130PDS shouldn’t be underestimated, although the stars are less perfect, it can still split some really tight doubles, beating the 102ED I would think (happy to be corrected) 
• Newts open up the possibility of viewing when standing - something I no longer do tbh, but does remove the need for a chair
• I prefer the eyepiece positions in Newts as you can rotate the OTA to get the perfect angle
• You can hug Newts while observing 😉

Having said all that, I generally use the 102ED now, and have lent my H130 to a friend! 🙂

 

 

Edited June 6, 2023 by RobertI

[Ratlet]

That's a fair amount to consider.

It sound like the azgti would be at it's absolute limit with this scope.  I'd put the az5 into a wobbly bob category as it is not as stable as the azgti with the 130pds.  Gem28 would be suitable, but using it for visual would remove that from imaging.  So doable, but not optimised for my current kit.

I had not considered the difference in observing style compared to my Newtonian on an alt az.  I find that to be very comfortable and convenient, although zenith can be a challenge to navigate.

I'm currently about 6 months out from a potential purchase so plenty of time to think it over.

Do any of the 102 user's have a preferred mounting style?  Alt az or eq?  I found the Newtonian to be more convenient in alt az as the eyepiece was predictable where it ended up.

 

[Franklin]

13 minutes ago, Ratlet said:

Do any of the 102 user's have a preferred mounting style?  Alt az or eq?  I found the Newtonian to be more convenient in alt az as the eyepiece was predictable where it ended up.

An alt-az mounted 102ED F/7 scope is grab and go heaven especially if using extra wide eyepieces but for high power planetary, luna and double star observing an EQ with tracking is a bonus. The positional problems with a newt on an EQ doesn't really happen with a frac as you can just turn the diagonal or the whole focuser quite easily, whereas with a newt on an EQ you've got to spin the whole tube in the rings.

Edited June 7, 2023 by Franklin

[bosun21]

I prefer an EQ mount for my Starfield and agree with @Franklin regarding the tracking at high magnification. Now if I had a nice Rowan mount with a Nexus attached I could possibly be swayed (maybe).

[Mr Spock]

I'm happy with the EQ5. It tracks nicely.

[Alan White]

1 hour ago, bosun21 said:

I prefer an EQ mount for my Starfield and agree with @Franklin regarding the tracking at high magnification. Now if I had a nice Rowan mount with a Nexus attached I could possibly be swayed (maybe).

Or have both and enjoy the good points of both.
Neither choice is right or wrong.