Refractor or Mak for my second telescope

[Hartmann]

I  have a 80 mm f5 refractor and i want to buy a bigger and new portable telescope and i consider two options , a 120 /600 skywatcher and a 127/1500 skywatcher mak, i know that there are perhaps better options like a 150-200 mm dobson but it must be very portable.

I have doubts about what tube could be better, 120/600 is more for wide fields and deep sky but for planets it will need a barlow, whereas the Mak is better for planets but it will need 35 or more wide field eyepiece, or focal reducer.

it will be used in planets,DSO,and i don´t will not use it for astrophotography .

what telescope is more flexible for all use ?

( In the future i want to buy or make a 200 mm dobson )

thanks
 

[jambouk]

I can only comment about the mak. It will be nice on the bigger and brighter planets. It will be nice on double stars. It will struggle with most DSOs, so i'd say it doesn't tick that box. It is portable.

James

[RichieP]

I disagree that the Mak will struggle with 'most' DSOs. You can still get a degree of field of view with this scope, and a lot of DSOs will fit into that, especially globs and planetary nebulae.

The ST120 will be great for wide field views but will struggle a bit at higher magnifications on the planets.

Neither scope is a great all rounder, but I would go for the Mak and keep your 80mm for wide field views.

Richard

Sent from my GT-I9305 using Tapatalk

[jambouk]

Field of view is one factor when considering the mak, but also the limited aperture means many globular clusters are pretty dim and it is difficult for my eyes to resolve much detail in them.

It is probably worth while getting to a star party and having a look through both to get a feel of which you prefer over a range of targets.

James

[happy-kat]

Is the other noteable difference between the two CA with one suffering when you ramp the mag up on planets?

[jambouk]

The last optical surface before hitting the eye piece for the mak is a mirror so chromatic aberration isn't a massive issue. CA would be an issue with an achromatic refractor, most noticeable i suspect when imaging which i think the original poster isn't wanting to do.

I do think, anyone wanting to observe DSOs should look at some through a range of telescopes before making a purchase. I suspect many people have high expectations of seeing great detail and colour - the reality in my experience with most telescopes is somewhat different. That is not to say i don't find DSOs fascinating, but i think it's important for people to know what they will be able to achieve before parting with hard earned money.

James

[Stu]

I think if portability is key, I would go for the Mak.

Assuming you are going to get to some dark skies, you have widefield covered with the refractor, so need to fill the gap for mid and higher powers. The mak will have a little less useable aperture than the 120 because of it's central obstruction but should be essentially CA free (maybe just a touch from the front plate but very little). Collimation is pretty stable on these scopes so it should handle transporting no problem.

As mentioned, many of the smaller DSO's will happily fit into the field of view of the mak with a low power ep, anything bigger like M31 you have the 80mm for.

Cooling is more of an issue, the mak will take longer, but if transported in a rucksack say, and kept in the car boot or whatever equivalent, it should not take too long to stabilise.

The key benefit would be planetary performance. The 120 would should appreciable CA at higher powers an in brighter objects, the mak should give that bit better and sharper views on planets, complementing the 80mm for widefield.

Any thoughts on what you would mount them on? The Mak should also be a little less demanding on the mount due to the shorter package.

Cheers,

Stu

[chiltonstar]

I have both an 80ED and a 127 Mak (5"). For diffuse objects such as M33, the little 'frac is better, but for objects like the Crab (M1) the 5" aperture of the Mak wins hands down. I would say as well I get as good a view with 5" as some are getting with bigger apertures in more urban locations - clearly a dark sky issue! Don't forget, M. Messier found his objects with long focus 3" or 4" 'fracs, but that was before the invention of the dreaded sodium lamp....

Is your location dark or LP'd - that for me would condition the choice of scope.

Chris

[ollypenrice]

The 120/600 is quite a nice widefield scope for low powers but has masses of false colour which would be plain nasty on the planets. The Mak has to be about the most portable scope for high quality planetary views. For a similar portabilty but a slightly wider field there's the 5 inch Celestron SCT. Then there are the apos in the 4 inch range. These give stunning widefield views and are excellent on the planets, reaching 200x easily. My list is in descending order of focal length, since the long focal lengths reduce the field of view.

Personally I'd go for the apo for a do-it-all compromise. There are variously branded 4 inch Chinese scopes at reasonable prices. Consider the SW ED100. It's a bit slow at F9. Then there are various triplets at F7 for a bit more field. Bang for buck the ED100 is a knockout. They come up used, too, because they are rather too slow for deep sky imaging once owners get into that.

Olly

[RT65CB-SWL]

Hi Hartmann and welcome to SGL.

I had the same or similar issue a few years ago as you. So I opted for the following portable 'grab & go' setup. My present OTA's are:-

TeleVue Ranger (d=70mm - f/l = 480mm @ f6.8) semi-achromat refractor

Meade ETX105* (d=105mm - f/l = 1470mm @ f14.0) maksutov-cassegrain

Celestron C6/SCT (d=150mm - f/l = 1000mm @ f15) schmitt cassegrain

With regards to mounting them, they take turns on a Tele Optic Giro mkll (manual alt/az mount) two at a time. (Though I am thinking about mounting all three whenI think of way to do it and if it is possible).

The ETX and SCT are great little planet killers asI observe lunar and planets mainly, because I have four sodium street lights nearby and local/town council are reluctant to turn them off between 00:00-05:30 and a supermarket.

+1 for Stu's/BigMakStutov & James'/jambouk comments.

* My ETX105 has been 'modded' and the rear flip-mirror assembly replaced with a back made from a single billet of aluminium by a local engineering workshop as the flip-mirror cell got damaged. I must remember to do a post about it. Believe it or not, I still have not had a night-time 'first light' since the 'modded' back has been on it, apart from terrestial use only during day-time.

[Hartmann]

Thanks for this useful information and advices.!

I think that i will go for the 127 mak and purchase a good wide field eyepiece for low magnification if i want to look DSO,

Thanks !

Sorry but I forgot to write in the Welcome thread, posting now

[jambouk]

Do some investigations about which eye piece you need for lowest magnification with the mak; you don't want to spend lots of money on an apparent wide field of view eye piece if the scope gives rise to a much narrower actual field of view.

James

[Stu]

It's a slow scope so you don't need to spend a fortune on ep's. A used 32mm TV Plossl would be a good bet, x47 mag and just over 1 degree fov.

A 24mm Panoptic would be great, though a lot more expensive. x62 with a similar fov and smaller exit pupil so darker sky background. The Plossl would be fine though, and pretty much the max field you can get with the scope.

Cheers,

Stu

[jambouk]

There you go, no research needed, Stu's done it for you

James

[happy-kat]

There is a great site I used you plug your scope in it says the capabilities, you then pick known eyepieces from a list to see how say the fov compares. I used this to choose my lowest mag eyepiece. Don't have the link on the tablet.

[jambouk]

Type "telescope field of view" into google and it will be the first hit.

James

[happy-kat]

This is what I used (on desktop so dug out link)

http://scopecalc.grid-itc.com/

[Stu]

I use a app called Luminos which does a similar job. I have all my kit in there.

Stu

[chrisbk]

I would be careful trying to get a decent field of view with the mak. The opening through the mirror is quite narrow, so a wide field eyepiece will vignette badly.

Chris

[Stu]

I would be careful trying to get a decent field of view with the mak. The opening through the mirror is quite narrow, so a wide field eyepiece will vignette badly.

Chris

I think a 32mm Plossl with 50 degree afov should be fine. Agreed that trying to use 2" ep's, longer focal lengths or wider afov's risks vignetting.

A Mak is a Mak at the end of the day and won't ever be a Widefield instrument.

Stu

[Big_Daz]

I personally like using this programme for AFoV because is also gives you a view of planets or messiers.

[StarryEyed]

I used a TV 32 in a 127 Mak with great results. The day I dropped the TV 32 and it cracked I nearly cried.

[Hartmann]

Finally i purchased a skywatcher 127 mak with a Plossl 32 mm eyepiece. it will be at home in the next days.

the next thing will be a new grab and go mount. because i had an azimutal mount  with a photo tripod,.