Some test objects with a 6" scope

[Moonshane]

I have recently seen a few threads where people ask what they can expect to see with a 6" scope. Last night I had reasonable darkness by 11.30pm and good clear skies with a quarter moon that had all but gone over the horizon. I therefore thought I'd try a few targets and attempt to be objective about what I could see. I had about an hour to observe as it's a work night.

My scope is a 6" f11 so may be somewhat different to any other 6" scope but for visual use it is mainly aperture that determines what can be detected. I am fortunate enough to use good quality eyepieces and have a range allowing many magnifications, especially at higher powers. I was using my home made equatorial platform which helps a lot at higher powers. I have given approximate magnifications so that people can compare their own scopes at the same powers if they wish. No filters were used.

My main targets were as follows:

Saturn - Cassini and planetary disc banding easily seen at 160x. The planet was low over roof tops and despite this the seeing was good and encouraging.

M57 Ring Nebula - This showed as a very distinct albeit small smoke ring even at 50x and at higher powers of 200x still showed the ring structure but with a diffuse central section.

M27 Dumbbell Nebula - the apple core shape showed well at 50x and this is a really obvious nebula even at 6" aperture. no sign of it in the 9x50 finder.

M13 Hercules Cluster - very obvious in the finder and showed mottling at 50x and from about 100x, stars were resolved sparsely all over the cluster. Optimum magnification seemed to be about 200x.

M92 - much smaller and dimmer than M13 but stars still resolved.

M5 - more compact that M13, some stars resolved and more emerged the longer I looked.

Double stars – This is my main double star scope and as expected the performance was excellent given the seeing. I managed to get to my maximum power on the night with the 6-3mm zoom used occasionally at 3mm (533x) and around 4-5mm (400-320x) gave more pleasing and equally effective views. Epsilon Lyrae (double double) was split well even at 160x with lovely airy rings around all four components. Delta Cygni was also split at 160x but much more obviously at 250x. Epsilon Bootis (Izar) is always a favourite of mine and easily split at 160x. Try as I might, I can never split Zeta Herculis. I suspect this is in its closest phase at the minute. Even at 533x there was no sign of a split although the airy ring seemed to be somewhat one sided indicating that the pattern was disrupted by the secondary maybe? Who knows.

In all a good night and I hope that this encourages people to look objectively at some of these objects and test their own equipment.

[stevetynant]

Shane- great post but you might want to rethink the text - its so small can hardly make it out

[Charon]

This is a very good report Shane.

[Polar Bear]

Shane- great post but you might want to rethink the text - its so small can hardly make it out

Are you using Firefox browser ? I use a mouse with a wheel and you can simply hold 'ctrl' down and the mouse wheel will control the size of the page. I am sure other browsers do this and it is good for when PEOPLE SHOUT IN THEIR POSTS !

Great little 6" report Shane. One thing you omited was location ? I was struggling to see anything (other than the Moon) last night and the sky was still blue at 11.30.

Paul

[Moonshane]

I am on a weird version of IE at work so have tried to change things. hopefully better now. location is 9 miles from Manchester

[stevetynant]

much better cheers - great post btw very helpful

[michael.h.f.wilkinson]

Nice report. Brings back memories of my old 6" F/8.

BTW, M97 should be M92. I have never been able to resolve stars in the Owl Nebula

[John]

Thats a very useful report Shane. The concept of "test objects" for an aperture was very popular when I started in the hobby but you don't hear it that often these days. They are a test of scope, conditions and observer !

As the seasons change I have favourite objects which I turn the scope on to as a challenge as well as being interesting objects in their own right - you have identified a number of them in this report. At other times I look for E & F in the Trapezium in M42, Plato craterlets, etc, etc.

As you get to know these objects you can quickly assess viewing conditions, the state of your scopes collimation etc.

[Moonshane]

cheers all - Michael - amended - must be a bit tired!

it surprises me sometimes when people say they are getting bored with looking at the same objects again and again. I often return to the old favourites and they usually provide something new or slightly different and even if they don't they are awesome anyway if you think what they are.

my key wish here is that the objects were all simple to find, and relatively challenging and can be returned to regularly over a period to gauge the differences.

[RikM]

Smashing write up Shane. I do much the same and use test objects to assess the sky conditions etc. Depending on the time of year M1, M51 and M97 are also on my list. Good nights I can see them quite easily, on poor nights there can be not even a hint.

[swamp thing]

Great idea Shane. This should really give people some indication of what can be seen through a 6" scope at a less than ideal location. Personally I think the location is great as its all to often we get to read what people have observed from incredibly good skies but seldom from an average one.

[Hals]

I agree that was an excellent report and tallies in very closely to what I can acheive with my 6" f6 (barring some of those very high magnifications).

It wasn't too long ago that a 6" was a decent aperture and anything greater than 10" was regarded enviously. How times have changed !

Still, I wouldn't want to be without mine - still an excellent scope and capable of a lifetimes enjoyment.

I always have a chuckle when I read about people moaning about the same objects to look at too - I really think if you tire of looking at, say, M57 over and over you're in the wrong game.

[Moonshane]

One thing occurred to me the other night when reading a post where someone was complaining about being bored with objects they see a lot. I am very lucky to have three excellent scopes, one of which has good aperture. using the smaller scopes sometimes in these short sessions reminds you how lovely the aperture of the bigger scope actually is. when you then look through the bigger scope again, you appreciate it a lot more I think, and things look completely different again.

and you thought there were surely not that many reasons to justify a large scope!

[stevetynant]

I've been pondering this very thing lately. I got an 8 Inch because of the recommendations on this site and being new to the hobby didn't want to spend a shed load of money only to be flogging it off on ebay 6 months later - thankfully that hasn't happened and hopefully I'll be here for the long haul - however. I'm probably never going to get a moosive aperture scope as my gardens just not condusive to it so I'm thinking 12-14 Inches max as a portable.

I do have an observing buddy who's speccing out a 22 to 24 Inch Monster Dob - the question is if you had a chance to look through something like this do you take it and run the risk of getting disillusioned with your scope or do you make do with what you have an be happy in the knowledge that even your own modest aperture scope is quite capable of seeing things that are only limited by your own ability to find them ?

[Moonshane]

here's my two justifications for not getting an enormous scope:

with your current scope at a dark site would show more objects than you'd probably cover in a lifetime of observing. more aperture just means that the brighter objects are more spectacular but also that you can see many thousands more objects. the bulk of these will be obscure galaxies and nebulae, many of which will not be in the mainstream star maps. many will be uninspiring visually but satisfying to see nonetheless if you 'collect' objects. understand though that whatever aperture you have, there will always be objects just outside of detection even in the best skies so it's pointless in my view to pursue aperture beyond a certain point.

my mate has a 22" f5 and it's a wonderful instrument. well built, attractive to look at and superb optically. BUT it has a 9 foot focal length so a ladder is essential for viewing, it will not fit through standard doorways and it is extremely heavy; the mirror weighs 60 pounds. for me this is too big and I'd personally not want to have to handle a scope that big. I have a 16" and this suits me well, maybe a 20" might be feasible if I could make one to fit through doors but it would preferably be a focal length of <f4 so I can observe on the ground most of the time. that said, this will be well beyond my budget for the forseeable future so I am really quite content.

I'd always urge people to retain a smaller 6-8" scope even if they do go big for the reasons mentioned above.

[Moonshane]

ps in answer to your query, use the (Matthew's??) scope and share the experience at dark sites with him, keeping the 8" for home use!

[michael.h.f.wilkinson]

I've been pondering this very thing lately. I got an 8 Inch because of the recommendations on this site and being new to the hobby didn't want to spend a shed load of money only to be flogging it off on ebay 6 months later - thankfully that hasn't happened and hopefully I'll be here for the long haul - however. I'm probably never going to get a moosive aperture scope as my gardens just not condusive to it so I'm thinking 12-14 Inches max as a portable.

I do have an observing buddy who's speccing out a 22 to 24 Inch Monster Dob - the question is if you had a chance to look through something like this do you take it and run the risk of getting disillusioned with your scope or do you make do with what you have an be happy in the knowledge that even your own modest aperture scope is quite capable of seeing things that are only limited by your own ability to find them ?

I have had my 8" scope for a long time (16 years), and have only in recent years (really since joining SGL) started looking beyond the Messier list. My DSO count has shot up (currently at 546), and I am finding more and more stuff. As Shane said, an 8" can keep you going for a long time. A 12 or 14 inch will show a lot more (I am aiming at something like a C11), and show more detail, but I will not sell the C8, as it is nice and portable. The best scope is the one you use most, and setting up an 8" ( especially for a quick look between cloudy patches) is a lot easier than setting up a 12".

[paul schofield]

Great informative post.

[knobby]

Top stuff Shane!

[Dunkster]

Thanks for that, really useful list. I've managed to enjoy all the Messier objects there plus Saturn with my C6, although with the LP around here M27 was a faint outline (enhanced with UHC-S, so I wasn't imagining it) and I struggled with M5 a bit... the C11 nailed that one much more easily

Now if only the clouds would box themselves back up, I'd like to tour them again.... alas Saturn will probably have to wait a while