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I want a 6 inch refractor. What can I see?

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#26 Jeff B

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Posted 17 April 2021 - 10:53 AM

I always have to ask, what's your budget, including the mount, and if it does do you want an EQ or alt/az mount.

 

And I'll comment with only refractors in mind and not pollute the thread with "For the same amount of money you can get an XYZ newtonian or SCT...." stuff.

 

Jeff


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#27 Defenderslideguitar

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Posted 17 April 2021 - 11:03 AM

Good topic  

 

It would seem that some 5 or 5.5 inch scopes come close to your goals.... The TEC 140 mentioned about would be wonderful in my view... My FS 128  seems bulky but surprising light and easy.

 

I also would love to be able to get an older AP 6 inch   even pre starfire but who wouldn't....

 

Back to the 6 inch though...have you thought about  the APM 152 or Evostar 150?

  I  have been reading threads about the APM 152  and the Evostar  150    on the affordable side of apo  6 inchers  and it would seem they might fit the bill for me and perhaps others like the OP.......

 

EDIT:  re reading the OP  it is an assumption perhaps I should not have made that an APO 6 inch is the 6 inch he might be looking for ....some achros might fit the needs for some


Edited by Defenderslideguitar, 17 April 2021 - 11:36 AM.

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#28 BillP

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Posted 17 April 2021 - 11:16 AM

I am currently very tempted by the TS-Optics 6" f/5.9 achromat. The price is not too bad at 922 Euros (currently $1105). The weight is 8.5 kg (about 19 pounds), which is a chunk, but not too unwieldy with a length of 900mm (about 36"). I think my heavy-duty SkyWatcher alt-az mount would handle it pretty well. I imagine that it would shine on the brighter clusters and nebulae and provide excellent wide-field views. Gathering over twice the light of a 4" refractor, it should have a real advantage with the brighter DSO's, and for that I would be willing to tolerate some CA on the Moon and planets. 

 

I had an Antares 152 f/6.5 achromat.  It was simply outstanding on everything except the Moon and planets.  Just too much CA to make viewing those enjoyable.  But on everything else I actually liked it more than my 10" Dob as the contrast was sublime.  Was very adept at high magnification also to get up close and personal with Glob cores!  At any rate, I think you might be quite happy with the TS as long as you get rid of your expectations relative to the Moon and Planets unless you do not mind stopping it down to 80mm - just use another scope for the Moon and planets!



#29 Defenderslideguitar

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Posted 17 April 2021 - 11:30 AM

BillP said:

Having a fork with cradle alt-az makes the lifting and attaching of the OTA much easier as well as just have to place it into the dovetail and it sits there stable unsecured, then tighten things up

 

That does seem practical and manageable

Say what is that fork cradle set up? Looks similar to the Gibraltar but



#30 junomike

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Posted 17 April 2021 - 11:38 AM

I like refractors. I don't want to mess up with a big Newtonian, so I am wondering if a six inch refractor could still give some nice views, also on deep sky. What about clusters and nebulae? What can I expect to see? Any experiences there? I could reach a bortle 4 sky in 30min and bortle 3 in one hour.. otherwise I am in a city pulluted area..
Thanks

If you're mainly planning on DSO's then I'd look for a used (or possibly new) 6" F5 Achomat over the conventional F8.  I had both and the F5 fits more, is lighter and requires less mount.

The trade off is at the expense of Planetary however IMO neither excel at that anyhow.



#31 David Stevenson

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Posted 17 April 2021 - 11:39 AM

The plan for me is buy an iStar lens and make the OTA myself. I was looking at the 6inch f6.3 apo triplet for a focal length of 910mm.
Also my intention was to fork mount it.

The first question was about DSO since planets and moon should be fine with the app, just wondering if I can get good views of some DSO like for example m13 M27 m31 M42 m45 m51 etc.. the show pieces...

#32 BillP

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Posted 17 April 2021 - 11:42 AM

Much stronger than a Gibraltar.  No longer produced but not all that hard to find on the used market.  Called a Helix Hercules mount head.  Pictured is their 8" model  I have a 10" one also.  They also made single arm ones for lighter loads.  Very smooth operation regardless of the tension setting.  On the used market typically around $250 for the head so quite a deal given their capability and performance.


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#33 John Fitzgerald

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Posted 17 April 2021 - 11:43 AM

The plan for me is buy an iStar lens and make the OTA myself. I was looking at the 6inch f6.3 apo triplet for a focal length of 910mm.
Also my intention was to fork mount it.

The first question was about DSO since planets and moon should be fine with the app, just wondering if I can get good views of some DSO like for example m13 M27 m31 M42 m45 m51 etc.. the show pieces...

Yes, you can get good views of those showpieces, but be aware that you will still have ONLY six inches of aperture.



#34 Jeff B

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Posted 17 April 2021 - 11:44 AM

In the "APO" world, on the lower price side , the F8 SW150 ED seems like a great deal and reasonable in size and weight.  Based upon my experiences with similar sized instruments (heavier actually) a Losmandy GM8 class mount with a Losmany HD class tripod will work just fine for high power visual work.  

 

In my direct experiences, my 6" refractors have real world light grasp similar to that of a C8, though, of course, resolution is lower.

 

Jeff


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#35 John Fitzgerald

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Posted 17 April 2021 - 01:04 PM

An Atlas EQ did not seem to be quite enough to hold my 6" triplet solidly, although it's only about 26-27 pounds, all up.  Obtained a Losmandy G11 and sold the Atlas.  The G11 is solid.


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#36 Mitrovarr

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Posted 17 April 2021 - 01:14 PM

I like refractors. I don't want to mess up with a big Newtonian, so I am wondering if a six inch refractor could still give some nice views, also on deep sky. What about clusters and nebulae? What can I expect to see? Any experiences there? I could reach a bortle 4 sky in 30min and bortle 3 in one hour.. otherwise I am in a city pulluted area..
Thanks

A 6" refractor is a substantial pain in the butt. I have a 10" dob and a 6" refractor and the refractor is easily the more obnoxious instrument to deal with and set up. More difficult than a 10" SCT as well. So you're not avoiding effort with a 6" refractor... they're physically huge for refractors and the mount you need is also large.

 

Aside from that, they're great! Fantastic planetary and double star telescopes. Pretty good on deep sky. They punch well over their weight on open and globular clusters due to the increased sharpness and pinpoint starts. Nebulae and galaxies benefit less, but still significantly. A 6" refractor is pretty good at everything except faint galaxies, where the 6" of aperture is not really enough (although it's still acceptable because of the high contrast).


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#37 TOMDEY

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Posted 17 April 2021 - 01:33 PM

All depends on how you mount it really.  I do not image or bother with automation so I just star hop to everything I want to see.  As a consequence of that my mounting for my 6" f/8 Apo is a simple fork-type alt-az mount head on a tripod from a CG5 mount.  Entire thing is rather light and I can pick it up and move it mounted without much problem and have carried it in and out of the house to yard fully mounted.  When I do use 2 trips to set it up, I many times leave the tripod with legs collapsed.  Once the scope is on it I just tilt the tripod and extend one leg, then repeat the process with the other legs until all are fully extended.  Not difficult or dangerous process.  Other times I just fully extend the legs first and lift the OTA.  Again, depends on the OTA but I believe mine is about 25-30 lbs with rings and finder and diagonal so not all that heavy.  Having a fork with cradle alt-az makes the lifting and attaching of the OTA much easier as well as just have to place it into the dovetail and it sits there stable unsecured, then tighten things up.  If the dovetail was on the side, as it is for non-fork alt-az mounts, then it would be a major pain for one person.  The wide base of the fork is also very handy as I just dip down and put that on my shoulder then stand up and easy as pie to lift the entire rig that way with shoulder taking all the weight and walk it around the yard or into the house.

 

Yes! --- I second that, Bill!

 

I have my 152mm F/8 APO on the Manfrotto 161 MK2 HD Tripod with Binoptic fork. The Crank up-down is very ergo. I use it right from our (dark sky) back deck directly out behind our living room, no stairs or transport involved, other than a few feet out and in.

 

For any observing plan --- Logistics is 90% of the battle. When you have that optimized, the rest comes easy. Whether it's hand-held binos or a giant monster in a dome; it's logistics that makes or breaks the observing experience.    Tom


Edited by TOMDEY, 17 April 2021 - 01:36 PM.

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#38 Astrojensen

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Posted 17 April 2021 - 01:53 PM

I've posted these pictures multiple times already, but since no one else seems to have drawings to show what's possible with a 6" refractor, I'll post them again. The two first are done at the eyepiece of a 6" f/8 achromat, while the bottom one is done with my APM 152ED, all from a Bortle 3 zone.

 

gallery_55742_324_1407448826_25253.jpg

 

M51, observed March 12th, 2012, with my 150mm f/8 Sky-Watcher achro. Baader Maxbright bino, magnifications 30x, 60x, 80x and 120x. SQM 21.4. Somewhat hazy. NELM about 6.

 

 

gallery_55742_324_1407448479_24877.jpg

 

NGC 891 observed December 27th, 2011, with my 150mm f/8 Sky-Watcher achromat. Baader Maxbright bino w/ 25mm kellners, 48x and 10mm kellners, 120x. The dust band was not seen, but the bulge of the galaxy was slightly brighter on both sides of the band. Seeing was OK, but transparency was mediocre, with stars slightly soft from haze. The view is mirrored, to show how it appeared using a diagonal. The northern end of the galaxy was fainter than the southern end, but this was hard to show in the sketch. It also appeared a little shorter, for some reason.

 

 

gallery_55742_4772_31734.jpg

 

M27, observed July 27th-28th (midnight), 2020, APM 152/1200 ED, 9mm ES100 for most details, 17mm ES92 for the faint extensions. Clear, but white nights not quite over. Milky Way easily visible, NELM ~5.5 - 6.

 

 

Clear skies!

Thomas, Denmark


Edited by Astrojensen, 17 April 2021 - 01:54 PM.

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#39 RLK1

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Posted 17 April 2021 - 02:25 PM

I had an Antares 152 f/6.5 achromat.  It was simply outstanding on everything except the Moon and planets.  Just too much CA to make viewing those enjoyable.  But on everything else I actually liked it more than my 10" Dob as the contrast was sublime.  Was very adept at high magnification also to get up close and personal with Glob cores!  At any rate, I think you might be quite happy with the TS as long as you get rid of your expectations relative to the Moon and Planets unless you do not mind stopping it down to 80mm - just use another scope for the Moon and planets!

I have the same and I use a simple inexpensive  49mm Hoya FL-DAY filter to suppress the chromatic aberration of the moon or planets. I slip it into the secondary and let it lay on top of the lip above the mirror since it doesn't thread into the unit. To remove it, I invert the secondary and the filter drops into my hand. I find the scope taxes my CG5 mount and while it works for visual purposes, I wouldn't attempt imaging with it.



#40 rkelley8493

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Posted 17 April 2021 - 02:55 PM

No experience with a 6" refractor, but my 5" [130mm] would show almost as much detail as a 10" Meade SCT on most objects from my semi-light-polluted back yard. The SCT pulled ahead on globular clusters, planetary nebulae, and some of the very faint galaxies. However, on most of the faint & fuzzy objects, they were pretty close in comparison.

The Apo had better image quality, sharper optics, and better contrast; hands down winner on the Moon, planets, and star clusters [imho]. I ended up selling the SCT after a year with the 130 Apo. The only thing I miss about the SCT was the views of planetary nebulae. Everything else seems to look better through the refractor [to my eyes].

As others have mentioned, a 6" refractor is going to be massive, especially if it's a triplet @ f/7 or longer. That's not to imply that it wouldn't be manageable. 30+ lbs isn't that heavy for a grown man, but it's a bit unwieldy because of the length & girth.

You would also need a robust mount to carry the load. Do not underestimate the importance of a solid mount, it is your foundation. Telescopes come and go, but the right mount will last you a lifetime and should be able to support any optical tubes you acquire over the years. I've gone through 3 telescopes with my Atlas Pro AZ/EQ-G over the past few years and have another on the way [still being manufactured]. It's great to have a reliable mount that can handle anything you can clamp on to it. With the right mount, you'll never have to think about it again. 


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#41 Wildetelescope

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Posted 17 April 2021 - 03:09 PM

I have a 6 inch F9 triplet. I have seen dust lanes in andromeda and color stars in the double cluster from my Bortle 7-8 back yard. It is also a great planet scope. I use it visually with mu atlas pro and G11T. It is happiest o. The G11T on a pier . If you have mount capacity, the 6. Inch scope is great!

Jmd

I like refractors. I don't want to mess up with a big Newtonian, so I am wondering if a six inch refractor could still give some nice views, also on deep sky. What about clusters and nebulae? What can I expect to see? Any experiences there? I could reach a bortle 4 sky in 30min and bortle 3 in one hour.. otherwise I am in a city pulluted area..
Thanks



#42 BillP

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Posted 17 April 2021 - 03:46 PM

I have the same and I use a simple inexpensive  49mm Hoya FL-DAY filter to suppress the chromatic aberration of the moon or planets.

I tried a variety of filters when I had it, did not like any of them as they altered the natural color of things.  These instruments really are not meant for lunar/planetary, although it was not too obnoxious on Mars or Saturn.  Any use on such will always be a compromise so just a word to the wise for kmparsons not to get expectations up too high.  On all other targets it was quite capable.



#43 25585

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Posted 17 April 2021 - 04:17 PM

For 6" I have considered a 190 MNT. Apo like views, no coma, rich field & short enough for an AZ100 or AZ6 mount. Not as heavy as an apo frac, & much cheaper. Easily car portable.


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#44 BillP

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Posted 17 April 2021 - 04:42 PM

I always used to hear folks complain about significant cool down issues, weight, inconvenience of the eyepiece position (EQ mounted), and sometimes collimation difficulties with MNs.  Sure you want one??


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#45 rkelley8493

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Posted 17 April 2021 - 05:02 PM

I always used to hear folks complain about significant cool down issues, weight, inconvenience of the eyepiece position (EQ mounted), and sometimes collimation difficulties with MNs.  Sure you want one??

That's one of the main reasons I don't care much for reflectors. Spec wise and price wise, they appear to be ideal for visual observing. However, in practice, I'd have trouble reaching the eyepiece without some sort of height aid. I stand at a towering 5'7" so I'd rather observe from the bottom end of the optical tube rather than the top. Of course a Dobsonian mounted reflector would be more beneficial to those who are vertically challenged, but I don't really care for the Dob style mount, and my back yard is on a steep downhill slope which isn't very Dob-friendly.


Edited by rkelley8493, 17 April 2021 - 05:16 PM.

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#46 25585

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Posted 17 April 2021 - 05:50 PM

I always used to hear folks complain about significant cool down issues, weight, inconvenience of the eyepiece position (EQ mounted), and sometimes collimation difficulties with MNs.  Sure you want one??

Not sure at all. But a 6" apo takes time to cool too. The attraction of a MN is its rich field & short length & no CA as an achro would have. I would use alt az mounting so eyepiece position would not be a problem.


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#47 25585

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Posted 17 April 2021 - 05:58 PM

That's one of the main reasons I don't care much for reflectors. Spec wise and price wise, they appear to be ideal for visual observing. However, in practice, I'd have trouble reaching the eyepiece without some sort of height aid. I stand at a towering 5'7" so I'd rather observe from the bottom end of the optical tube rather than the top. Of course a Dobsonian mounted reflector would be more beneficial to those who are vertically challenged, but I don't really care for the Dob style mount, and my back yard is on a steep downhill slope which isn't very Dob-friendly.

I like large aperture & small expense, so a Dob is the solution for me. 

 

There are few comfortable seating positions or standing positions for me at 6' 2". An equatorially mounted seat & scope rig, so you both move as one may be idea...but expensive 


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#48 Chris K

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Posted 17 April 2021 - 06:10 PM

I have the Altair Astro Starwave 152 on a CEM40.

I can set up in about 30 mins, including all the trips in and out of the house.

It’s an achromat and only shows false colors on super bright objects like Sirius and Jupiter.

Otherwise it has inspiring views.
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#49 noisejammer

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Posted 17 April 2021 - 09:44 PM

I've owned a 6" triplet for more than a decade.

 

Observing from the city is challenging - no scope can cut through light pollution & do justice to nebulae like M42. Using a NPB filter an an observing hood, I could see the inner structure but the wings were impossible. I have glimpsed the Flame neb but it was really marginal.

 

Prior to COVID, I regularly took the scope to star parties and my experience was similar to Thomas' above. I'll report on it's performance under 22m skies after my September trip. For what it's worth, last time out, these skies gave me my best ever views *and I was only using a 4"*.

 

When using it for a look around, I mount it on a counter-balanced DM6 with a tall tripod and a 10" home-made extension. The altitude axle is at about 5'6" which works for me most of the time (I'm 6'4" tall.) I mostly binoview which counteracts the nose heavy structure.

 

Setup with the DM6 requires 4 trips - tripod & weights, mount and  cradle, tube, eyepieces. I can be up and running in less than five minutes.



#50 areyoukiddingme

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Posted 17 April 2021 - 10:01 PM

After owning a 6" F8 triplet, I concluded that it was more work that I was willing to undertake for a mere 6" of aperture.

 

As far as wrangling goes, it was about the same amount of hassle--for leaving the house to drive to a dark site--as my 16" Dob.

 

My conclusion was that for that amount of hassle of set up, I'd rather take the much larger aperture.

 

But I did have a lot of fun playing around with the 6" scope. The crisp views of the moon and punching surprisingly above it's weight on M81 and M82 are the two stand out recollections.

 

I was disappointed by how dim the planets were in the 6" compared with 12.5" reflector. 

 

So I see a 6" triplet (or possibly F8 doublet) being something that has uses for particular situations. Pehaps you only want one big refractor because you aren't a fan of reflectors and SCTs, and want to max out your aperture. A 6" refractor could certainly scratch that itch.

 

And if you carry them about in a soft case, and pair with an alt-az set up, you can at least minimize the pita factor.

 

For me, I like refractors and reflectors, and somewhere around 120-140mm is where I want to max out. After that I'd rather switch to a reflector.


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