Scope for terrestrial observation and astrophotography

[Icesheet]

As the title says I would like a scope that can be used for terrestrial observation and for astrophotography. I know there is no solution that is ideal for both and that I will be compromising somewhere. I initially set out to get a spotting scope and a small astro refractor but ultimately that will cost more than I want to pay (~£500). 
 

So I’m wondering how many here use their small refractors for terrestrial observation too and how it stacks up against a decent spotting scope if you have one? I’m thinking along the lines of EvoStar 72ed, WO Zenithstar 61 etc. 

Edit to add: 

I already have a 2” star diagonal with 1.25” adapter and various eye pieces so I’m covered in that department. Would take recommendations on a good zoom eyepiece if any though!

 

Edited July 25, 2020 by Icesheet
L

[Alkaid]

I use my 102 achromat frequently for terrestrial use.  What I have found is that the best views are over water (no thermals).  You can’t really push high powers for long range terrestrially due to the air currents coming off the land so the achromatic refractor at low power (x20) works quite well, with a wide field of view and is inexpensive.

[Icesheet]

Actually it will mostly be used for views out over water. To some islands a couple of miles away and a distant glacier. I’m curious to know how far you’ve been able to push it when looking out over water? I suppose early in the morning or later in the evening is best

[Alkaid]

You know, if it is predominantly over water as you say, an ED refractor would be better. You’ll be able to push the power a bit without any thermals ruining the image. Perhaps a little 72mm ED or 80mm ED model would be more suitable?

Over water, my short focal ratio achromat starts to produce “poor” images at about x50.  An ED version would go much higher if required.  Don’t forget though that the wide field of view is also desirable and you get that with lower powers.

[Icesheet]

Yeah I’ll be looking at an ED model as I’ll be using it for imaging too. I’m thinking the SkyWatcher EvoStar 72ed could be the way forward. The OTA and reducer/ flattener would be in budget. 

[Moonshane]

Bear in mind you will need a correct image diagonal (prism) for terrestrial use or your image will be left right reversed. Maybe this is not an issue though for stated use.

[Highburymark]

SW72 would be a good choice - or a secondhand Equinox 80ED for around £300 would be perfect. F/6.25 so great for imaging, and a capable spotter too. 

[Icesheet]

10 minutes ago, Moonshane said:

Bear in mind you will need a correct image diagonal (prism) for terrestrial use or your image will be left right reversed. Maybe this is not an issue though for stated use.

Yeah, I read about that. I think I’ll get my head round it and I will just be scanning landscapes mostly so either way I don’t think I’ll be fussed. 
 

That looks like a nice set up @Highburymark. Wouldn’t mind your view and climate too! You don’t mind the 90deg diagonal for terrestrial stuff then?

[RT65CB-SWL]

How about a 'small' Maksutov or SCT?

The downsides are is...

• the long focal length; (I have an ETX105 and is f/14 or thereabouts).
• dew magnets - a dew shield is a must have accessory and is not included.
• cooling time of thirty minutes [minimum] if used for astronomy; (visual and imaging).
• narrow field of view. (not yet tried with an FF/FR reducer from my C6/SCT-xlt).
• expensive as are dedicated photographic mirror lenses.
• left/right - east/west is reversed.

 

The upsides is that they...

• compact size.
• are excellent lunar and planetary 'scopes.
• hardly require collimation.
• can be attached to photo/video tripod and suitable head. 
• up/down - north/south is right way up.

Edited July 25, 2020 by Philip R

[Paz]

A 45 degree diagonal is useful for spotting, but takes up quite a lot of light path. I have used a ST80 for spotting and it only just has enough in focus with a 45 degree RACI diagonal.

Edited July 25, 2020 by Paz

[Highburymark]

1 minute ago, Icesheet said:

 

That looks like a nice set up @Highburymark. Wouldn’t mind your view and climate too! You don’t mind the 90deg diagonal for terrestrial stuff then?

Sadly it was taken 5 years ago on holiday in the Canaries. And I no longer have the Equinox but that doesn’t prevent me recommending it as a terrific all round scope.

In terms of terrestrial observing, it really depends what you want to do. Birding really requires a correct image diagonal. The good thing about faster EDs like the Equinox or Esprit is they give lovely wide views with a well corrected 2” eyepiece

[Alkaid]

32 minutes ago, Philip R said:

How about a 'small' Maksutov or SCT?

The downsides are is...

• the long focal length; (I have an ETX105 and is f/14 or thereabouts).
• dew magnets - a dew shield is a must have accessory and is not included.
• cooling time of thirty minutes [minimum] if used for astronomy; (visual and imaging).
• narrow field of view. (not yet tried with an FF/FR reducer from my C6/SCT-xlt).
• expensive as are dedicated photographic mirror lenses.
• left/right - east/west is reversed.

 

The upsides is that they...

• compact size.
• are excellent lunar and planetary 'scopes.
• hardly require collimation.
• can be attached to photo/video tripod and suitable head. 
• up/down - north/south is right way up.

Phillip, I think the issue with a CAT is narrow FOV.  For terrestrial you really do need a bit of wide field to open up the view I feel.  Whilst a CAT can work well for looking at say a bird, it can take a while to find the bird whilst you’re panning around.  I reckon the refractor would be a better match.  Cheers Steve

[robhatherton]

A decent Ed spotting scope would of course be waterproof if that matters. 

[Icesheet]

@Philip R I did consider an SCT/ Mak but that was too much of a compromise for imaging. Too long FL and asking too much of the small mount I would use. I do have plans for a bigger SCT in the future though. Would love to do some serious planetary imaging. 

 

10 minutes ago, robhatherton said:

A decent Ed spotting scope would of course be waterproof if that matters. 

I’m more of a fair weather spotter so while being waterproof would be nice it’s not vital. I would rather get more in terms of my optics. 

[Moonshane]

How can it be waterproof?

[Icesheet]

1 hour ago, Moonshane said:

How can it be waterproof?

Most good spotting scopes these days are weather sealed and purged with nitrogen. 

[Alien 13]

The trouble is that even a small 70mm frac will require a 2 inch correct image diagonal (which are as rare as hens teeth) to get decent low magnification views so it might be better to get a dedicated imaging scope and a pair of binos.

Alan

[Icesheet]

2 hours ago, Alien 13 said:

The trouble is that even a small 70mm frac will require a 2 inch correct image diagonal (which are as rare as hens teeth) to get decent low magnification views so it might be better to get a dedicated imaging scope and a pair of binos.

Alan

I’ve been down the bino route, with a pair of Swarovski EL’s no less. The optics were first class but the 8.5x just didn’t cut it for what I was observing. I’ve also bought a second hand pair of 100mm BT binos but that’s not turned out as planned and  I’m ready to cut my losses there. 
 

I can live with left/ right inverted  images as long as they are the right way up which is what I believe I will get with the 2” star diagonal I already have. I know I’m compromising whatever I do really. 

[Icesheet]

1 hour ago, KevS said:

One of the things you have to bear in mind is do you intend to remain in one spot or are you mobile. For most terrestrial use a 80mm spotting scope is overkill, especially if you are carrying it the tripod and other kit for a day out twitching; although you can buy specific backpack type carriers to alleviate the load. I have a 85mm Zeiss that very seldom leaves the house for that reason. I have a 65mm Vanguard HD, which is of reasonable quality that is the go to workhorse for a day out walking and mobile twitching, but even that starts to grate after about 5 miles or so. 

I will mainly be observing from one spot but I did want it to be compact enough to take on the occasional trip either for spotting or imaging. Maybe you want to let your Zeiss go! 😉

[Icesheet]

Actually the Pentax 65ED and 80ED were on my spotting scopes list. Not actually sure how spotting scopes would do for imaging though. 

[robhatherton]

Some spotting scopes like the Celestron regal take 1.25 Astro eyepieces so I’m sure you could attach a camera. 

[Ricochet]

9 hours ago, Icesheet said:

Actually the Pentax 65ED and 80ED were on my spotting scopes list. Not actually sure how spotting scopes would do for imaging though. 

I think that photography would show up a touch of CA, and you might find that you can't reach focus. I know that with my PF65EDA I can't focus if I try to use a barlow in front of the eyepiece. For a spotting scope that will be carried on walks I think 65mm is a good size. If I was to replace it I would only be looking at Swaro/Zeiss 65mm scopes, not larger objectives. 

[Icesheet]

50 minutes ago, robhatherton said:

Some spotting scopes like the Celestron regal take 1.25 Astro eyepieces so I’m sure you could attach a camera. 

The Regal M2 80 was another on my list. It’s whether it would be suitable for imaging like @Ricochet says. 

I think I’ll probably go down the small Ed doublet route. Should give me a nice balance on both fronts