8 inch dob or 80mm apo?

[doublevodka]

Don't get me started on the multiple scopes route @Xilman I already want one of these... https://www.firstlightoptics.com/alt-azimuth-astronomy-mounts/sky-watcher-az-gtix-dual-saddle-alt-azimuth-astronomy-mount.html

Although by your locations and kit list, I suspect you do things in a much more professional capacity than me

[Xilman]

34 minutes ago, doublevodka said:

Don't get me started on the multiple scopes route @Xilman I already want one of these... https://www.firstlightoptics.com/alt-azimuth-astronomy-mounts/sky-watcher-az-gtix-dual-saddle-alt-azimuth-astronomy-mount.html

Although by your locations and kit list, I suspect you do things in a much more professional capacity than me

Looks good to me.  I won't buy one because I have no immediate use for it.

I also have a cruddy Newtonian on a GEM which hasn't been used for over 5 years. I have been giving serious consideration to adding a DSLR to its counterweight so that wide-field photography for bright-star photometry, serendipitous discoveries such as meteors, etc  can be made while peering through the Newtonian at other things. A Canon 1000D cost me £20 on eBay, sold as "for repair or spares" because it will not take exposures shorter than 30 seconds. While crippling for terrestrial use it is ideal for astronomy. Ancient lenses don't cost much more than that either.

[Mr Spock]

Interesting mounts. But, need setting up for tracking. That's why I prefer my EQ5 - I call it "plonk and go"  I just stick it in the right place on the patio and switch it on.

[doublevodka]

2 hours ago, Mr Spock said:

Interesting mounts. But, need setting up for tracking. That's why I prefer my EQ5 - I call it "plonk and go"  I just stick it in the right place on the patio and switch it on.

Used to do very similar with my eq3-2 and the simplicity of the tracking was great, my ability to find things, not so much 🤣

To be fair to the az-gti I have which is similar to the above it's not much slower to do, plonk down north and level, do the north level alignment routine which is just pick 2 stars from a list and center the objects when the scope gets close, adds maybe 2 mins but means I can find what I want 👍

That's the great thing about this hobby, so many ways to do it, so it can suit everyone 👍

[Mr Spock]

11 hours ago, doublevodka said:

That's the great thing about this hobby, so many ways to do it, so it can suit everyone

That's what I keep saying 

[Xilman]

16 hours ago, Xilman said:

 A Canon 1000D cost me £20 on eBay, sold as "for repair or spares" because it will not take exposures shorter than 30 seconds. While crippling for terrestrial use it is ideal for astronomy. Ancient lenses don't cost much more than that either.

Just picked up a Canon EF 18-55 mm on Ebay for £11.50 + £3.95 postage. Even less than the camera. Another spares or repairs job.  The autofocus doesn't work in this case.  AF is completely useless for astronomical work anyway.

So: a wide-field imaging system for a marginal cost of less than forty quid. I already have the telescope for narrow -field work and a mount for both of them. An hour or so and a lump of scrap metal sheet should be all that's needed to complete the job.

Also have my eye on a 80-200 for a similar price.

[Guest]

I shouldn't knock a 80mm refractor, they make such good finder scopes for big reflectors.  

[cajen2]

Mike's the only person I know who has a Stellarvue.....and uses it as a finder! 😛

[Guest]

16 minutes ago, cajen2 said:

Mike's the only person I know who has a Stellarvue.....and uses it as a finder! 😛

And the problem with that is exactly what? 

[cajen2]

Nothing at all... it's just that for many people, a Stellarvue is an aspirational scope....😉

 

[Stu]

25 minutes ago, cajen2 said:

Mike's the only person I know who has a Stellarvue.....and uses it as a finder! 😛

Have you not heard of Magnus’ little Stellarvue finder? 😉

 

[Guest]

1 hour ago, cajen2 said:

Nothing at all... it's just that for many people, a Stellarvue is an aspirational scope....😉

 

It really is just a Stellarvue finder, but what an image 

[Xilman]

6 hours ago, Mike Q said:

I shouldn't knock a 80mm refractor, they make such good finder scopes for big reflectors. 

Here is the kit inside my dome.

As you see, a Vixen R120S also makes a fine finder.  (In reality, the finder is barely visible metallic object the other side of the white scopes.  It is home-made from a discarded achromatic lens.)

The chap in the photo is the guy from whom I bought the observatory almost 5 years ago now.

[Guest]

38 minutes ago, Xilman said:

Here is the kit inside my dome.

As you see, a Vixen R120S also makes a fine finder.  (In reality, the finder is barely visible metallic object the other side of the white scopes.  It is home-made from a discarded achromatic lens.)

The chap in the photo is the guy from whom I bought the observatory almost 5 years ago now.

Now that is sweet

[Xilman]

On 01/03/2023 at 16:55, doublevodka said:

Although by your locations and kit list, I suspect you do things in a much more professional capacity than me

I wish to state that I am not now and have never been ... a professional astronomer.  (With acks to Tom Lehrer.)

Everyone can do good scientific research work if they put in some well-targeted effort. Expensive equipment in an optimal location might be desirable but it is very far from being necessary. In the field of astronomy a pair of binoculars used in a suburban back garden is easily adequate. Existence proof for this assertion: George Alcock.

All you need to do is to get your ass into gear (to use an American colloquialism), record what you observe, and then publish your observations.

Are you up to the challenge?  You may get fame, fortune and glory as a result.  Well, fortune is vanishingly unlikely but fame is certainly on the cards.

 

[Jules Tohpipi]

On 25/02/2023 at 22:04, doublevodka said:

First the background, I'm a visual observer and likely to stay that way, I usually have limited time so quick setup and go is important to me. I love the az-gti for this, up and running in minutes, but I find myself hankering for a wider field of view than the skymax 127. The az-gti is also a plus for finding objects quickly

 

 

Just a double-check here in case you didn't realise. The field-of-view, for any given eyepiece, is not much wider in an 8 inch dob than your Skymax 127. Whereas the 80ED does have a much wider field of view.

Of course, the dob is an excellent telescope but the FOV and magnification are on a par with your existing mak. The views in the eyepiece will be the same size roughly but brighter and more detailed. If you are seeking a brighter and more detailed view then jump in. But if your priority is a much wider view then the 8 inch dob won't deliver that. 

Conversely, the ST102 works a treat on the AZ-GTi and gives a wider field of view than the dob/mak. Plus, as you are visual only, you won't need to worry about its CA when looking at dimmer/fuzzier targets - you'll be using the mak for brighter objects like planets and the moon. And the ST102 has got more aperture than the 80ED.

 

 

 

Edited March 5, 2023 by Jules Tohpipi

[doublevodka]

14 hours ago, Jules Tohpipi said:

 

Just a double-check here in case you didn't realise. The field-of-view, for any given eyepiece, is not much wider in an 8 inch dob than your Skymax 127. Whereas the 80ED does have a much wider field of view.

Of course, the dob is an excellent telescope but the FOV and magnification are on a par with your existing mak. The views in the eyepiece will be the same size roughly but brighter and more detailed. If you are seeking a brighter and more detailed view then jump in. But if your priority is a much wider view then the 8 inch dob won't deliver that. 

Conversely, the ST102 works a treat on the AZ-GTi and gives a wider field of view than the dob/mak. Plus, as you are visual only, you won't need to worry about its CA when looking at dimmer/fuzzier targets - you'll be using the mak for brighter objects like planets and the moon. And the ST102 has got more aperture than the 80ED.

@Jules Tohpipi you raise an interesting point there that wasn't on my radar. Out of interest, with the kit you have, 250 Dob, Skymax, 127 and ST102, which gets used the most?

Having owned reflectors, refractors, and cassgrains I'm leaning toward the refractor a little just because I prefer the contrast they give (and being able to carry out with one hand is a big plus), but I'd be interested to know your thoughts on your own kit.

[bosun21]

31 minutes ago, doublevodka said:

@Jules Tohpipi you raise an interesting point there that wasn't on my radar. Out of interest, with the kit you have, 250 Dob, Skymax, 127 and ST102, which gets used the most?

Having owned reflectors, refractors, and cassgrains I'm leaning toward the refractor a little just because I prefer the contrast they give (and being able to carry out with one hand is a big plus), but I'd be interested to know your thoughts on your own kit.

I actually sold my 102 Apo frac and I prefer using an 8SCT and 12” dobsonian. I use the SCT when the moon is up and the dobsonian for the darker nights. This is totally subjective of course and I am not wishing to start the frac/reflector/ SCT debate.

[Stu1smartcookie]

I  have an 8" Dob , which i honestly love ( hope wife doesn't read this ) ... and ive had an 80mm APO ... the 80mm is a fine scope but the Dob is so much more , in fact i have a 150mm frac but the dob still gets more use at present . Mind you if i was to give advice on what Dob to get then i would certainly say that the StellaLyra dobs offer the best "extras" in the package . 

Dual focuser , Fan , nice bearings on the base and a decent 30mm EP . 

 

 

[Ratlet]

If the idea of chromatic aberration bothers you with the ST102, a similarly priced reflecting alternative would be the 130pds.  Great 2" focuser for visual and fantastic widefield views.

Apparently they work well for imaging too, I tried mine once and it did a good job but since then the only thing on the end of the focuser has been an eyepiece and my eyeball.

Works nicely on the azgti mount as well.

Edit: I type this knowing full well that I've committed my greatest online sin, suggesting a third option when someone asks for a choice of 2!  But for widefield observing I think the 130pds is underated.

Edited March 6, 2023 by Ratlet
Show awareness that my comment may not actually help.

[Jules Tohpipi]

4 hours ago, doublevodka said:

@Jules Tohpipi you raise an interesting point there that wasn't on my radar. Out of interest, with the kit you have, 250 Dob, Skymax, 127 and ST102, which gets used the most?

Having owned reflectors, refractors, and cassgrains I'm leaning toward the refractor a little just because I prefer the contrast they give (and being able to carry out with one hand is a big plus), but I'd be interested to know your thoughts on your own kit.

The straight answer is I use the Skymax 127 the most.

Context being I like looking at views that change somewhat e.g. Jupiter and its moons, the other planets and our moon. After that it’s clusters and comets. The Skymax is intended to replace my 250 dob GOTO eventually as it’s getting used less and less due to my back when moving it around. The GOTO adds a lot of weight to the dob. Sure the dob gives good views on my favourite targets but the mak is more than good enough at giving the scale of things in the eyepiece and the detail I need - it seems a trivial sacrifice compared the better convenience. Actually, targets are slightly larger in the mak than the 8 inch dob. 
 

This would be a very different matter if I were going out to dark sites to look at faint fuzzies. Alas, I never did get around to doing that with the big dob and my local skies are disappointing for such viewing.  So the mak is my new favoured instrument. Also bear in mind with a manual 8 inch dob under medium LP skies, star-hopping can be a real challenge. That’s why I moved from 8 inch manual dob to the 10 inch goto. 
 

The ST102 is the newest addition. After many years, I realised I didn’t necessarily want always to look at max magnification. But just take in the wonder of the stars themselves. It’s a great partner for the mak in that regard and its weight is ideal for the AZ-GTi too. It literally adds a new dimension to things and I like that. Plus it was a low cost addition. The weaknesses of the ST102 are 90% covered by having the mak to hand. 

I don’t necessarily want to put you off buying the 8 inch dob. By experience I know it to be the biggest bang for the buck out there. But it’s not that much a different beast to your existing mak except on the faintest of targets. Consider it a higher resolution, brighter mak (with similar mag and FOV but no Goto and more cumbersome. Albeit I found the 8 inch manual quite easy to move around). Consider it if your priority is dimmer stuff  Then buy the frac too for a proper wide view 😀

 

 

Edited March 6, 2023 by Jules Tohpipi

[Stu1smartcookie]

As above , the ST102 is a tried and trusted Achromat that shows star clusters and bright dso's very well ... but of course there is no substitute for aperture and the Dob also excels on planetary viewing . With NO chromatic aberation . I have a 127 Mak ( bresser ... true 127 mm ) that shows stunning planetary and luna views so i do get where Jules is coming from . The Maks do have their own issues though of narrow FOV and longer cool down times . 

Remember the saying .... No one scope excels at everything . 

[Xilman]

4 hours ago, bosun21 said:

This is totally subjective of course and I am not wishing to start the frac/reflector/ SCT debate.

Oh what a shame!  I just love a vehement religious war where everybody is wrong and everybody is right.  One can learn so much from other people's strongly held views.  😉

 

[doublevodka]

17 hours ago, Stu1smartcookie said:

Remember the saying .... No one scope excels at everything . 

I don't need convincing of this, the wife however.... 😂

[doublevodka]

13 hours ago, Xilman said:

Oh what a shame!  I just love a vehement religious war where everybody is wrong and everybody is right.  One can learn so much from other people's strongly held views.  😉

This is why I love SGL, it's mostly friendly and sensible with balanced views as nicely demonstrated in this thread 👍

Some other forums, however, not so much 😂