Help re 180 Maksutov and C8

[Paz]

I've been lookimg for a 180 Maksutov second hand for some time with no luck and in doing so notice there are a lot more Celestron C8's coming and going second hand.

This has got me thinking about whether to go for a second hand C8 as an alternative until a Maksutov comes along, or simply instead. Ive googled it to death and have read most of the stuff thats out there, I was just wondering if sgl colleagues can provide any new or further  experiences that would help to understand and make a decision.

The purpose of the scope  is something to go in the gap between my st120 and vx14, small and light enough for an eq5 mount, visual observing only, compact for storage, not a refractor or newtonian because i like to experience different kinds of scope. Cool down time doesnt matter. Ive recorded what i observe and wide fields of view is a bonus but not a necessity based on my observing habits. Sharp views and detail are more important. I homed in on a the idea of a 180 maksutov because i like my 127 maksutov a lot, and I'm used to good quality views in the vx14. A 7 or 8 inch wont compete on detail or light gathering but it does need to be reasonably good quality wise.

As well as being interested in any observations that occur to others I have a coupke of particular queries...

Is an edge c8 noticeably better visually than a normal c8 or it it really only for imaging?

Ive noticed carbon fibre c8's, how heavy are they? A normal c8 is 5.7kg, which is pushing what an az4 or porta2 can carry (or is it?). If a carbon ota is much lighter and light enough for an az4 or porta 2 that would be a major benefit as it would allow for more flexible grab and go opportunities.

Any comments would be welcomed!

[John]

Having owned a C8 and (for a short time) a 180 mak the one thing I will say is that both would be rather too much for the AZ-4 or Porta 2 IMHO. Add a dew shield (mandatory for either scope) and the situation gets even less viable.  A Skytee II is OK with both although the long focal length and narrow FoV of the 180 mak really makes manual tracking challenging. Your EQ5 might be OK with the C8 but I'm not quite so sure about the 180 mak.

They are both great scopes - just need a capable mount to get the best from them. The 180 mak produces sharper stars and a little better planetary contrast I feel but the C8 is more versatile.

[Luna-tic]

1 hour ago, Paz said:

 

Is an edge c8 noticeably better visually than a normal c8 or it it really only for imaging?

Ive noticed carbon fibre c8's, how heavy are they? A normal c8 is 5.7kg, which is pushing what an az4 or porta2 can carry (or is it?). If a carbon ota is much lighter and light enough for an az4 or porta 2 that would be a major benefit as it would allow for more flexible grab and go opportunities.

Any comments would be welcomed!

My Edge 8 has a much sharper field than my C6, but unless you looked in the C6 and then into the Edge, you wouldn't notice the coma too much in the C6. Still, Edge is worth the extra dollars if you can swing it.

The carbon fiber tube isn't noticeably lighter than the steel one; the carbon's advantages are in temperature stability, expansion/contraction.

[Moon Watcher]

Mak Cass or Mak Newt?

[nightfisher]

5 hours ago, John said:

Having owned a C8 and (for a short time) a 180 mak the one thing I will say is that both would be rather too much for the AZ-4 or Porta 2 IMHO. Add a dew shield (mandatory for either scope) and the situation gets even less viable.  A Skytee II is OK with both although the long focal length and narrow FoV of the 180 mak really makes manual tracking challenging. Your EQ5 might be OK with the C8 but I'm not quite so sure about the 180 mak.

They are both great scopes - just need a capable mount to get the best from them. The 180 mak produces sharper stars and a little better planetary contrast I feel but the C8 is more versatile.

I would say Johns post hits the point nicely, i had the 180 on an EQ5 and it struggled, on that basis i would suggest the C8 as its lighter and yes a dew shield is essential on either scope

[Chris]

I've heard it said that the 180MAK is for ever chasing thermal equilibrium due to the corrector plate being so very thick. It's also very heavy and has a very long focal length with no possibility of using a reducer as with SCT's, so I wouldn't want to use one with an AZ4 personally, I just feel it would be too much.

I've briefly used a 150MAK on an AZ4 and that was really pushing things, but I have a feeling a 150MAK would work well with an EQ5, not sure if the 150MAK would suit you?

I've also owned both the C8 xlt and C8 Edge and the later is sharper hence more like the MAK, plus it's lighter and cools more quickly and can be reduced, very nice scope. Having said this when I used a 0.63 reducer with the C8 xlt it sharpened up nicely, just not quite as much as the Edge.  

[Pete Presland]

I would say the C8 is a bit more of an all rounder of the two. The Mak180 has Focal Length: 2700mm (f/15) ideal for planets, double stars, Moon. I had a Mak180 for several year and had no complaints regarding its performance though. Some great views of the planets and the Moon. 

I think the C8 would be ok on the EQ5, obviously an HEQ5 would be better option though. As John has said a dew shield is essential, a heated one if your can.  

[michael.h.f.wilkinson]

My C8 has been working admirably on my Vixen Great Polaris mount for close to 22 years. As the EQ5 is a clone of the GP mount, I would guess the EQ5 mount should be OK. The C8 OTA is the lightest 8" OTA I know, and it is a great all-round visual scope, and neat planetary and lunar imager. It is also easy to take on holidays with the car. Haven't used an Edge ever, so cannot comment on visual differences, but even with my Nagler 31T5 "Panzerfaust" I do not really notice coma.

[chiltonstar]

On other fora, there are frequent mentions of C8 scopes with poor optics -presumably these quality failures get sold on to some poor mug.

I've not found cooling much of a problem with my 180 Mak, but it is heavy and needs a good mount, and can track fairly easily at X 300 on an alt-az mount with patience.

I like the view through a good C8, although the field edge stars did not impress me......

Chris

 

[RobertI]

1 hour ago, Lockie said:

Having said this when I used a 0.63 reducer with the C8 xlt it sharpened up nicely,

Yes I have also found using the 0.63 reducer produces really nice small stars. I assumed this was due to the low magnification, but I never had time to compare the same magnification views with and without the reducer so could never confirm whether it was the reducer producing the small stars or not. Anyway I love using the C8 at relatively low powers of 50-60x plus the high power planetary views can be amazing - it's a versatile scope. i'm afraid I can't comment on the Mak though as I have never owned one.

[michael.h.f.wilkinson]

The 0.63 reducer is labelled "Reducer Corrector". I gather it also corrects for field curvature and coma. I have one, but only use it photographically

[Astro_king]

30 minutes ago, michael.h.f.wilkinson said:

The 0.63 reducer is labelled "Reducer Corrector". I gather it also corrects for field curvature and coma. I have one, but only use it photographically

Do you use a DSLR with it?

I read somewhere here that the distance between the focal reducer 0.63 and the DSLR chip has to be 110mm.

When I checked my T adapter gaining into the telescope, it was merely 70mm or something like that.

How do you achieve focus?

I can't test as forecast isn't clear for a while

 

[michael.h.f.wilkinson]

11 minutes ago, Astro_king said:

Do you use a DSLR with it?

I read somewhere here that the distance between the focal reducer 0.63 and the DSLR chip has to be 110mm.

When I checked my T adapter gaining into the telescope, it was merely 70mm or something like that.

How do you achieve focus?

I can't test as forecast isn't clear for a while

 

I have used it with my DSLR, using the standard Celestron T-adapter the distance should be OK. I had no issues with my crop-sensor camera on lunar imaging. It does cause vignetting on my old 35 mm SLR, as the image circle is reduced to 28mm or so.

[John]

4 hours ago, Moon Watcher said:

Mak Cass or Mak Newt?

The 180 is a mak-cass. The 190 is a mak-newt.

[Chris]

1 hour ago, michael.h.f.wilkinson said:

The 0.63 reducer is labelled "Reducer Corrector". I gather it also corrects for field curvature and coma. I have one, but only use it photographically

Yes, it helps correct these errors, it's not optimised though, the corrector needs to be positioned inside the OTA for optimum correction which is exactly what the Edge variant of the C8 does. 

[Peter Drew]

1 hour ago, michael.h.f.wilkinson said:

My C8 has been working admirably on my Vixen Great Polaris mount for close to 22 years. As the EQ5 is a clone of the GP mount, I would guess the EQ5 mount should be OK. The C8 OTA is the lightest 8" OTA I know, and it is a great all-round visual scope, and neat planetary and lunar imager. It is also easy to take on holidays with the car. Haven't used an Edge ever, so cannot comment on visual differences, but even with my Nagler 31T5 "Panzerfaust" I do not really notice coma.

This has also been my experience. The Vixen GP mount is far better than the EQ5 clone and easily holds a C8. I recently bought an elderly classic C8 and the optics are superb. I've not noticed edge of field coma, basically as I never look for it. Most of the "bad" C8's these days are just badly collimated ones.   

[Stu]

2 minutes ago, Peter Drew said:

This has also been my experience. The Vixen GP mount is far better than the EQ5 clone and easily holds a C8. I recently bought an elderly classic C8 and the optics are superb. I've not noticed edge of field coma, basically as I never look for it. Most of the "bad" C8's these days are just badly collimated ones.   

I use a C9.25 on a Vixen GP mount and with a solid tripod it is quite ok for visual.

[chiltonstar]

21 minutes ago, Stu said:

I use a C9.25 on a Vixen GP mount and with a solid tripod it is quite ok for visual.

I've balanced my 180 Mak on my Vixen SP and it is at the limit, but works.

Chris

[JG777]

Have a read of this http://www.astro-baby.com/reviews/Skymax 180/Skymax 180 Review.htm

 

[25585]

12 hours ago, John said:

Having owned a C8 and (for a short time) a 180 mak the one thing I will say is that both would be rather too much for the AZ-4 or Porta 2 IMHO. Add a dew shield (mandatory for either scope) and the situation gets even less viable.  A Skytee II is OK with both although the long focal length and narrow FoV of the 180 mak really makes manual tracking challenging. Your EQ5 might be OK with the C8 but I'm not quite so sure about the 180 mak.

They are both great scopes - just need a capable mount to get the best from them. The 180 mak produces sharper stars and a little better planetary contrast I feel but the C8 is more versatile.

I use a SkyTee-2 with my C8. It's about the most stable alt az mount you can buy commercially. Very solid and needs a good tripod to put in on. 

[Paz]

Thanks very much for all the comments - they have helped me to organise my thoughts.

I think I will broaden my horizons and consider C8's as well. I would hope to have many good observing years ahead and over time hopefully will get the opportunity to own/use both types of scope (but not at the same time!).

The issue of weight and a sufficient mount I had put to the back of my mind thinking the 180 would be fine on an EQ5 but I realise that is over optimistic if I really think it through. This makes a C8 more of a goer as if I have to get a beefier EQ mount it all moves out my own personal definition of grab and go territory, and if that happens these scopes would no longer be filling the niche I'm looking to fill.

A Skytee 2 is fine with me, and I may trade off my AZ4, AZ3, and some other bits and get a Skytee 2 but a HEQ5 would be more metal than I would prefer!

Now it's a waiting game for the right thing to come up second hand, I just need to resist the temptation to buy anything new at the Stoneleigh show!

[Luna-tic]

13 hours ago, Astro_king said:

Do you use a DSLR with it?

I read somewhere here that the distance between the focal reducer 0.63 and the DSLR chip has to be 110mm.

When I checked my T adapter gaining into the telescope, it was merely 70mm or something like that.

How do you achieve focus?

I can't test as forecast isn't clear for a while

 

Not sure how they measure between them (C6 and C8) as far as  focus distance goes, but I've had no problems focusing my C6 with a 6.3 reducer, 2" Baader back, 2" diagonal and T-adapter with my DSLR (crop sensor). I'm looking forward to trying the 0.7 reducer for the Edge, whenever they become available again. 

[Paz]

The change of strategy has worked, it didn't take long to find a C8!

They are certainly good in being a lot of aperture in a small and light scope. It will be interesting to check out the views.

The only problem now is I have to sell the ST120 or the MC127, but which one!?

[Peter Drew]

1 hour ago, Paz said:

The change of strategy has worked, it didn't take long to find a C8!

They are certainly good in being a lot of aperture in a small and light scope. It will be interesting to check out the views.

The only problem now is I have to sell the ST120 or the MC127, but which one!?

I would be inclined to sell the 127MC, the ST120 would be a better complement to the C8.