8" dob, now what??

[Adamke (Adam)]

Gday, thought id join a forum to get a bit of insight and experience and see how everyone rates the scope i have and what i should be achieving.

Got given a saxon 8" dob as a gift. Been wanting one a while but hadnt done alot of reseach into them recently.

Had it out the last 3 nights, middle of suburbia, full moon, standard eye pieces. Im impressed but cant help but wonder if this scope is at its limits and what improvements i can now do.

I picked up a 2x barlow which made viewing better, although still a little disappointed with clarity, size and colour of both planets and DSOs. Now i understand the city lights wouldnt be helping.

Had a good look at the moon, mars, saturn and jupiter, the and the jewel box. Stock eye pieces are 25mm and 10mm


My scope was outside for many hours so temp was ok, all cleaned eye pieces, everything was high in the sky. So whats next??? Get some better quality 1.25" eye pieces in an array of sizes? Head out to darker areas? Ditch the barlow? Bigger dob???

Sorry for all the questions but just a bit bummed. Cheers

[raymo]

Hi Adam, Firstly, no matter what scope you have, the planets will only be at their best from time to time when the "seeing" is really good. When the
seeing is average the detail will come and go, and you will get short bursts of great viewing.
Apart from some planetary nebulae, only a tiny number of the brightest DSOs will exhibit a hint of colour, usually green or pale pink. For most DSOs there is no substitute for a dark site to view from; makes a huge difference. Try to view objects as high in the sky as possible, so you are looking through less atmosphere. A light pollution filter can help, as can a decent nebular filter.
Better quality eyepieces will improve matters, but not hugely. Don't ditch
the barlow unless it is junk. Most people have one or two in their armoury.
Pretty useless viewing DSOs when there's much of a moon, you need all
the darkness you can get. Bigger dob you don't need at this stage, in fact
quite a few people stick with an 8". When you have learnt some of what is where up there, and have improved your seeing skills, you can decide if
you want to upsize.
raymo

[astro_nutt]

Hi Adam. I can relate on how you feel. In 2000 I was the proud owner of the same scope. I had read up on how this scope performs via the magazines available at the time. After trying a few spots away from the burbs, I found the views were better but skyglow was still a problem. The next step was to join the Astronomical Society of Victoria and then visit their dark sky site. This is where the full potential of the scope came through. I learned how to collimate and fine tune the mechanical relationship of mirrors, focuser and finderscope. Next was learning how to look through the eyepiece. Letting your eye accumulate the photons to complete the image. I have moved on from the 8 "dob but it is still in use with excellent optics and a very happy owner. An 8"dob is a great instrument in which to learn the sky and to learn how reflecting telescope work.
Never be sorry for asking questions, it's how we all learn.
Cheers!

[Chris.B (Christopher)]

Full moon is boring through any scope. What you want to do is follow a full cycle. a few day old moon is a challenge but the details you see is amazing. Craters and mountains stand out when lit at dawn or dusk, just like here on earth.
Under city lights no scope will that good as the contrast is just not there.
Head out of town on a moon less weekend and you will amazed what an 8 can show you.
Dark site you will have 100x more detail and you will never run out of targets. Messier catalogue is a great starting point.
Don't hunt anything but planets around full moon. Just wait a week and you will see a huge difference in detail even in the city.

[grimsay (Iain)]

Hey Adam,

I have pretty much the exact same 'scope as you (8" Sky-Watcher) which I picked up in January. And I'm also viewing from suburbia, Newcastle in my case.

There's heaps to see with the 8" and I've not even scratched the surface. Once I get to some darker skies things will only get better, DSO particularly. Ultimately it all comes down to expectations.

To date I've viewed the 3 planets in good viewing just now, plenty of Open and Globular Clusters (stunning), loads of Double Stars (probably an acquired taste), some Planetary Nebulae (cool but need darker skies I think) and some of the brighter Galaxies (hard to find and a bit dull from light polluted suburbs).

Originally I was a bit disappointed viewing Jupiter at 120x (the 10mm in our case) but then I picked-up a couple of higher power eyepieces to see more detail. Now I check it out all the time for different happenings and appreciated the 120x for its own reasons compared to higher powers.

The biggest factor towards enjoying a night and not getting frustrated I found was making a target plan for the evening based on the conditions, what was up and targeting a specific constellation(s) or target type e.g. an all doubles night. I also go a Telrad which made finding things easier.

There are some great lists around for things to find. I use Robert Horvarts guides a lot (member here). And decide what to look at by magnitude I know I can see and best time to view.

I'd also recommend checking the collimation of your 'scope asap - I just bought a cheshire and collimated mine for the first time this weekend... much improved seeing.

Hope this helps. Don't be to bummed, you've got as great scope with heaps to work with.

Cheers, Iain

[janoskiss (Steve H)]

Most important thing is to learn how to collimate the scope. You will find clear instructions online, e.g., in the Orion XT Dob manuals, or in a Sky & Telescope article on the topic: "collimating Newtonian". I'd recommend a visual Cheshire style collimating tool over fancier gadgets like lasers because it's more reliable; a laser collimator will itself need collimating. (Without regular collimation a Newtonian will perform poorly. Collimation for a telescope is kind of like wheel alignment for your car.)

There is lots to see with an 8" f/6 Dob, which is a fantastic insturment. It's way too early to think about going bigger. The 2x barlow is a good addition but you'll be able to make better use of it if you also get a 12-15mm eyepiece. The 10mm Plossl barlowed will push the magnification too high on most nights. Also plossls around 10mm are at the limit of what I consider comfortable because of the short eye relief / small eye lens. No need for expensive gear: a 15mm fully multi-coated plossl for <~ $50 would do nicely.

Seeing you're in Brisbane, it'd be worth visiting Astro Pete's telescope shop, see http://astropetes.com.au/ and having a chat with the guy. By all accounts he's an exceptionally helpful, honest and knowledgeable astro-gear dealer. I'm sure he'd give you good advice.

What make barlow did you get btw?

[barx1963 (Malcolm)]

Hi Adam and welcome to IIS!!

Congratulations on the scope. The 8" dob is in many opinions, including mine, the ideal beginners scope. the reasons for this opinion are several but the main ones are that they are easy to setup, easy to use, relatively inexpensive, easy to sell if you decide visual astronomy is not for you, transportable and have enough aperture to see a lot of "stuff".

As to what you are seeing, "full moon, middle of suburbia" is ticking the 2 main boxes of less than ideal observing conditions. the good news is that the first one will be improved in a few days and you will see a major difference in the views of deep space objects. If you manage to get out to a dark site (and being in Vic I cannot really advise about that in Qld!) you will see even more.

One thing to be aware of is that you will never see things like the wonderful images that you see on this site and others on the net, but tink about the fact that the light you can capture in that scope in amny cases has travelled for thousands or millions of year to reach it. And of all the billions of people in the world, there are only a very small number who have the chance to view these wonders of our universe - and you are now one of them!!

On a mor technical note, I am guessing the scope came with a 10mm and 25mm eyepiece? With your barlow, that gives you effective FLs in your eyepiece box 25, 12.5, 10 and 5, which should be more than enough to go with for a start. My usual advice, especially with viewing DSOs is "use the eyepieces you have for a while". you can spend (read "waste") a lot of money chasing improvements via eyepieces, but unless you have a clear idea what you need you can end up with just a full eyepiece box and an empty wallet. If you have a 25mm plossl or similar, that will handle most of your observing for a long time. I used almost nothing else for a bout a year in my 8" and 12" dobs that i started with.

Anyway, hope this all helps!!

Cheers

Malcolm

[Adamke (Adam)]

Hey all and wow thanks for the responses. Had the scope out again tonight just because i can, took a step back and used the 25mm on the moon for while.

The barlow i believe is a saxon branded 2x achro barlow. It works ok but still after cleaning i can see a few faint dots on the lense.

Ive been doing a bit of reading tonight and i think i will look at collimating the scope as people have recommended it,even coming from new.

Went to a sirius optics in brisbane the other day and had a look at some nice looking eye pieces, some that were larger to the eye, and my 10mm is a bit of a strain. Was looking at a 9mm but may try around the 12-15mm as suggested.

Didnt have the scope out in the weather for long tonight and i was getting some bad "starring"?? On mars, 4 opposite lines in a cross shape. Would this be due to temp or a poorly aligned scope???.

Anyways will persist and am looking forward to the moon dulling out and hopefully more clear nights to havw a good look.

Havent written the scope off yet, just think i need to be persistant and make sure its set up right.

Thanks for the insight!

[dimithri86 (Dimithri)]

Hey Adam. I am in a similar situation to you. Once your eyes are properly adapted and there is no moon, you can see quite a few DSO's nicely. Sometimes it a bit underwhelming at how much detail or brightness you can see. What I do is just look at them anyway, because it gives me practice finding things, so when I go to a dark place, I can find things quicker and make better use of my time.

I have a imaging setup too, but I like spending a few hours a week looking through my beginner scope. Ill try and find a link for you regarding developing your eyes. It actually takes practice to get the most out of your eyes, so even though your views might be underwhelming, its a process you have to go through to develop your observing skills.

[janoskiss (Steve H)]

The Saxon 1.25" achro 2x barlow will probably do you for starters but in the longer run you might want to get something better...(?? hard to say for sure because Saxon have three different models out). Bit of dust or small marks on the lenses won't affect the view in significant way. Collimation is by far the most important thing to get right especially for mid-to-high magnifications.

The "cross shape" you mention is likely normal: it sounds like diffraction spikes from the "spider" (the four steel vanes that hold your secondary mirror in place).

[Cimitar (Evan)]

Originally Posted by Adamke

... So whats next??? Get some better quality 1.25" eye pieces in an array of sizes? Head out to darker areas? Ditch the barlow? Bigger dob???

Sorry for all the questions but just a bit bummed. Cheers

Hi Adam, I agree with what others are saying, however just thought I'd add a different perspective based on my personal experience. In short, visual astronomy doesn't excite me. I owned a 5 inch scope and was disappointed/bummed with the experience. So I switched to a 16 inch dob expecting to see more (I live in a very dark site) and was still disappointed. I then bought better eyepieces, a UHC filter etc. to no avail. I enjoy nebula and galaxies the most, but they're called "faint fuzzies" for a reason!

So, I started doing some basic astrophotography with my DSLR and a $25 tripod. You can get 25sec subs using an 18mm lens, on ISO 6400 I was able to achieve some awesome images of the Milky Way (including colours in nebula via processing). I then sold my 16 inch and I've now gone down the path of a modest imaging telescope rig to chase my galaxies (I rarely do visual work). I still get out the trusty $25 tripod occasionally though to take some wide field shots! Have a look in the nightscapes image gallery to see what's possible.

Clear skies!
Cheers, Evan

[Atmos (Colin)]

Originally Posted by Cimitar

Hi Adam, I agree with what others are saying, however just thought I'd add a different perspective based on my personal experience. In short, visual astronomy doesn't excite me. I owned a 5 inch scope and was disappointed/bummed with the experience. So I switched to a 16 inch dob expecting to see more (I live in a very dark site) and was still disappointed. I then bought better eyepieces, a UHC filter etc. to no avail. I enjoy nebula and galaxies the most, but they're called "faint fuzzies" for a reason!

So, I started doing some basic astrophotography with my DSLR and a $25 tripod. You can get 25sec subs using an 18mm lens, on ISO 6400 I was able to achieve some awesome images of the Milky Way (including colours in nebula via processing). I then sold my 16 inch and I've now gone down the path of a modest imaging telescope rig to chase my galaxies (I rarely do visual work). I still get out the trusty $25 tripod occasionally though to take some wide field shots! Have a look in the nightscapes image gallery to see what's possible.

Clear skies!
Cheers, Evan

The one warning I can give with what Evan is suggesting... Once you catch the imaging bug your cash reserves just disappear before your very eyes

[janoskiss (Steve H)]

@Evan The 5" to 16" was probably too big a jump: a 5" Newtonian (?) is somewhat aperture and in other respects challenged, while a 16" consumer Dob (like GSO, SW etc) requires time and effort to get it to perform well. An 8" Dob is much more likely to deliver the goods for someone starting out.

@Adam re what Evan wrote: You've got to at least get a good look at Saturn and her rings on a good night (when the atmosphere is still) before you decide visual astronomy is not for you. Also check out a few Jupiter moon shadow transits. Note that the atmosphere is still enough to make the most of an 8" f/6 Newt only relatively infrequently. So a bit of patience and persistence pays off. But even on better than average nights you should pick up a fair bit of detail on the gas giants. On nights of poor-to-average seeing (roughly about half the time when it's clear), the atmosphere will very noticeably blur what you see through the EP at mid-to-high powers (over ~150x).

[Nab (Darren)]

Hi Adam,

Being a Brisbanite transplanted to Ballarat I get home often enough to compare the skys. On the outskirts of Ballarat NELM is often around 4-4.5, on most clear nights away from the moon you will see the band of the Milky Way, and LMC/SMC and some other deep sky objects.. all naked eye.

In Brisbane suburbia you are probably luck to get much past a NELM of 2-2.5 with considerable light pollution making the sky look light and views of everything washed out. You will also have to deal with a thicker atmosphere from being near sea level, and suspended sea spray (especially if you are near the bay), not to mention all the lumpy air generated by a higher density of houses, roads etc..

The dark adaption your eyes will also be an issue. In my outer suburban back yard, which is across the road from state forest it is easy to find a relatively dark spot - This won't be the case in Brisbane with more neighbour’s lights, street lighting (both from your street and the one behind) and the generally more bright environment of the city. This will also limit what you can see, and limit how things that you do see appear in the eyepiece.

Certainly take the advice of others - check collimation, it makes a huge difference, wait for a moon free period and revisit from DSOs and see the difference it makes, and I'd say also stick to lower power - your 25mm plossl should give you more than pleasing views across a range of objects from the moon to brighter galaxies ... if you can find dark enough skys to see them

cheers,

Darren.

[Kunama]

The unfortunate side effect of Astronomy suppliers' marketing is that beginners expectations of what they will see at the eyepiece are never realized.

If you consider how far some objects are and how long it has taken for those precious photons to travel to reach your eye you can only marvel in awe at the view. The problem with astrophotography is that those actual photons never reach the eye, they merely create a splat on a charge couple device.......

[janoskiss (Steve H)]

Perhaps it's worth mentioning, because a lot of beginners don't realise it, that planets are very bright objects and are unaffected by light pollution.

[Cimitar (Evan)]

Originally Posted by Atmos

The one warning I can give with what Evan is suggesting... Once you catch the imaging bug your cash reserves just disappear before your very eyes

Yep, Colin's spot on with this one. The words "money pit" spring to mind. Yet astrophotography is strangely satisfying oddly enough. Not the money part obviously! 2 weeks ago I imaged the relativistic jet emanating from M87. Objects such as these are incredibly difficult to see visually, hence why I (generally) prefer imaging over visual. Having said that imaging is a path that's not to be taken lightly and patience is definitely a virtue.

Originally Posted by janoskiss

... You've got to at least get a good look at Saturn and her rings on a good night (when the atmosphere is still) before you decide visual astronomy is not for you. Also check out a few Jupiter moon shadow transits.

Adam - I'd certainly encourage you to try Steve's recommendations about observing Saturn and some Jupiter moon shadow transits. This will help you discover the available options under the big banner of astronomy. Another way to find your particular niche could be to read astronomy magazines. I particularly enjoy Australia Sky & Telescope, All About Space, and Astronomy (I have no affiliation with any). These mags have helped me to fine-tune my interests. When I first started I promised myself I'd never do imaging (and yet here I am ). I also had zero interest in radio astronomy, however as the years tick by I become ever more intrigued.

Originally Posted by Kunama

The unfortunate side effect of Astronomy suppliers' marketing is that beginners expectations of what they will see at the eyepiece are never realized.

Matt's right - so true. I've known friends who've looked through a telescope, hoping to see what's on the box, only to be disappointed and sadly bow out. The key takeaway is if you remain disappointed after looking through the eyepiece, try to figure out why. That way you can hopefully take steps to correct it

Cheers, Evan

[Anth10 (Anthony M)]

An 8" I was once told is the perfect sized visual scope(newtonians). There doesn't seem to be as much turbulence in the tube compared to the larger sized scopes and less cumbersome to handle. I had plenty of fun with the 8 I once owned. I'll never forget M83 viewed at Bass on a night of perfect seeing. Amazing. 47 Tuc and Omega Centauri are brilliant targets using a 25mm Ep. I would consider getting a nebula filter H beta. This will certainly enhance views for DSO's in particular old favourites such as Orion and Carina Nebs! Have fun out there, maximise your potential with your 8". Time spent will better your skill and appreciation of visual observation.

[Stonius (Markus)]

I would add that a lot of visual astronomy is about pushing your visual acuity to its limits. Fine details are often transient because of atmospheric conditions. You'll get a flash of detail and have to wait a moment to be sure when the same detail flashes again. The longer you look the more you'll see in grabs and spurts.

But I would also say about half of it is knowing what your selected object is supposed to look like and what additional details can be seen. The rings of Saturn are easy to see, but can you see the Cassini division? How about the Encke Division? The C ring? Any cloud detail? How many moons can you spot? Programs like Jupiter 2 can help you know where the red spot is at any one time, or which moons are doing what. A good lunar program can help you find fine details on the moon. And faint fuzzies are *faint. You'll be stretching your eyes to the limit to try to grab those photons that give you more detail. In images they look like the fires of the universe, but through a telescope they look like gossamer thin balloons or bits of cotton streched across the night sky. You have to work to be sure of what you're seeing, and again, knowing what the target looks like gives you a good indication of what you're trying to see.

And on top of that, knowing about what you're looking at increases the sense of wonder. When you spot Titan you know it has an atmosphere thicker than earth's. On Mars, you catch a glimpse of Olympus Mons and know that if you stuck that volcano at the bottom of Earth's Mariana trench, it'd still tower 2km higher than everest.

It's kind of an extreme sport for the senses. And yes, as with other extreme sensorial pursuits, like wine tasting or audiophile listening it can disappear into the void between perception and invention, but don't let that ruin the fun. As long as you're enjoying it, that's what counts :-)

Markus

[mental4astro (Alexander)]

Hi Adam,

to IIS.

Sage advise has been forwarded on to you here. I won't add anything to the scope thing as there is plenty for you to digest and it will only make for noise.

What I will add is to suggest you will gain a lot if you are able to get along to either a formal or informal club or astro gathering. You will be able to share in the collective wisdom of such a group, pick up practical tips as sometimes it is best if someone shows you how to do something rather than try to wrestle it out yourself (collimating your scope can be such an exercise where being shown makes the learning curve a lot smoother).

There is a BIG astro meet happening at the end of July that goes on into the start of August, the Queensland Astrofest. It attracts astro nutters from all over the country. The info that you will pick up there will serve you a lifetime. Below is a link to the Astrofest thread here in IIS's Star Parties Forum:

Queensland Astrofest thread link

I'll be heading up for the second weekend, Will be my 3rd Astrofest

Alex.