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Old 24-04-2019, 11:09 AM
bluesilver (Peter)
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Telescope for Planetary viewing and DSO's

Hi, sorry if this is kind of repeating a bit on what my previous thread was, but thought i would be best to start a new thread on this particular topic,

So apologises if i have gone about it wrong here.

So i currently have the Skywatcher 10 inch goto Dobsonian.
I would like to do both planetary viewing and also get more into the DSO's
I was looking to upgrade to the 16 inch Skywatcher goto Dobsonian as i figured it would be better at viewing the DSO's, but thought i would also be better for planetary viewing.

From some good advice, i have learnt that this may not be the case for planetary viewing, but the 16 inch would be good for the DSO's.

Would something like the SkyWatcher Black Diamond 180/2700 Mak-Cassegrain be great for planetary viewing?
I am looking for something fairly decent for planetary,
From what i have researched so far, it sounds like SkyWatcher Black Diamond 180/2700 Mak-Cassegrain would be an improvement from my 10 inch Dob.

I currently have been using the Tele Vue 10mm Delos, Hyperion 5mm eye piece, Tele Vue 2.5x powermate, plus the two standard 10mm and 25mm eye pieces that cam with it.

But any information to put me on the right track here would be appreciated.

I hope i am not going over old stuff that has been asked many times before, but all information is appreciated.
Thanks.
Peter.
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Old 24-04-2019, 03:12 PM
Startrek (Martin)
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You have a great scope there Peter in the 10”and should be able to resolve many DSO’s without the need to upgrade to a monster of a telescope in the 16”
I had a 10” non Goto dob for years and recently upgraded to a 12” Goto which is a big as I will ever need
Firstly to observe most DSO’s you need low power eye pieces from 17mm up to 30mm
My favourite eye piece for nebula and globular clusters are the ethos 21mm and for galaxies my 24mm and 27mm Panoptic. Sometimes I use the Delos 17.3mm but not that often

Planetary require medium to high power eye pieces depending on seeing conditions in the 13mm to 4.5mm range. I use my Ethos and Delos eye pieces for planets
For lunar just about anything will do and again seeing conditions determine what’s best
To add to the range I have a set of Televue Powermates plus various UHC and planetary filters

It’s entirely up to you but your 10” will do the job nicely provided your not chasing +12 magnitude objects , the real dim faint fuzzies
Hope the above helps
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Old 24-04-2019, 07:55 PM
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If space and money were no objects ( pun intended ) a Celestron C14 would be the best for what you want . You would have to spend 10x more to get 20% more performance .

But a 10 inch Dob is no slouch and the 180 Mak would be awesome for planets , personally I would keep the Dob and grab the 180 for those excellent nights there they really shine on the Moon and Planets .

Your eyepieces would perform well in the Mak but your smaller ones would get EXTREME high powers so a 12-14mm and 32-40mm would be great , Plossls perform well at the sizes .

My 5c .

Brian.
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Old 24-04-2019, 08:10 PM
raymo
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Brian is spot on, the 180 is an ideal planetary scope.
raymo
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Old 24-04-2019, 09:10 PM
GodsPetMonkey
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The 180 Mak is certainly a good planetary scope, but I think the first question you need to ask yourself is how is your current dob letting you down and how will the Mak (or any other new scope) address that.

Looking at your list of gear, you should have to trouble hitting atmospheric limitations - the powermate plus 5mm eyepiece would give you a healthy 600x magnification, and that would require some extraordinarily good seeing to pull off! Even the delos with the powermate would see your dob hit a more manageable 300x magnification (and is a very nice combo too). Your powermate effectively turns your 1200mm dob into a 3000mm dob - pretty comparable to the 2700mm Mak, except your dob has an extra 70mm of aperture.

Actually, I think your equipment 'weakness' is actually at the other end, you are lacking a nice wide-end eyepiece for the bigger DSOs and beautiful star fields. You need to upgrade from that included 25mm job!

The Mak does have a few pluses - it's smaller and lighter than the dob, which means you might be more likely to use it if you have to move your score around. They are pretty hassle free and are will known for their performance on the moon and planets - if you are big on viewing the planets having such a dedicated instrument can make a lot of sense. Having two scopes can also mean you can hunt two different objects at the same time (or share your viewing with others more easily!).
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Old 24-04-2019, 09:15 PM
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Camelopardalis (Dunk)
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Peter, a 10” newt can be very versatile, and give excellent results with the planets if well collimated. The scale of the details on Jupiter for example really test the limits of the seeing too, so really make sure your collimation is perfect...it can really make all the difference.

As for DSOs...there’s no substitute for aperture, but 10” is still a good sized scope. If you don’t already, try visiting a dark site as that will really show you what your scope can do.
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Old 24-04-2019, 10:25 PM
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Yes very good points ,,, But

have you ever viewed Jupiter in one of the best 10 inch SW Dobsonions at ,,, say 500x on an excellent night ? ,, you know when the view is like a Hubble photo ? . I have as a good friend who is member here and has one of the best reflectors I have ever had the pleasure to look through it's ,, a Sky Watcher 10 inch Dob , this scope is amazing taking 6-700x with ease ,,, but ,,, the viewed object goes so fast on an Alt/Az mount .

At 500x where a good 10 inch is still not breaking a sweat , the Dob mount has run it's race and it gets hard fast really fast , true my friend .

FF to a Mak 180 on say a driven EQ/HEQ 5 mount at 500x on the same night .. , I will leave it here as it's " Horses for Courses "

Me I am lucky to have a great C9.25 that does it all , and a few 4-5 inch refractors but that is not the OP's 'Q '

Brian.
Quote:
Originally Posted by GodsPetMonkey View Post
The 180 Mak is certainly a good planetary scope, but I think the first question you need to ask yourself is how is your current dob letting you down and how will the Mak (or any other new scope) address that.

Looking at your list of gear, you should have to trouble hitting atmospheric limitations - the powermate plus 5mm eyepiece would give you a healthy 600x magnification, and that would require some extraordinarily good seeing to pull off! Even the delos with the powermate would see your dob hit a more manageable 300x magnification (and is a very nice combo too). Your powermate effectively turns your 1200mm dob into a 3000mm dob - pretty comparable to the 2700mm Mak, except your dob has an extra 70mm of aperture.

Actually, I think your equipment 'weakness' is actually at the other end, you are lacking a nice wide-end eyepiece for the bigger DSOs and beautiful star fields. You need to upgrade from that included 25mm job!

The Mak does have a few pluses - it's smaller and lighter than the dob, which means you might be more likely to use it if you have to move your score around. They are pretty hassle free and are will known for their performance on the moon and planets - if you are big on viewing the planets having such a dedicated instrument can make a lot of sense. Having two scopes can also mean you can hunt two different objects at the same time (or share your viewing with others more easily!).

Last edited by brian nordstrom; 24-04-2019 at 10:38 PM.
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Old 25-04-2019, 09:26 AM
bluesilver (Peter)
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Hi, I appreciate all the advice and answers, exactly what i am looking for.
I don't really have any clubs around here close by, best one is at the other end of the state, about 3/12 hours drive unfortunately.

I do have good clear unpolluted skies here, nearest street lights / town lights are a good few kilometres away and i live on a 200 acre farm property.

So from the sounds of things so far, as a few have advised me, my eye pieces i am trying to use for DSO's are not right, i need wider ones, around the 25 mm.
That helps explain a lot to start with.

The only issue with planets that are letting me down and this could just be my setup / collimation, i am using the laser collimation tool for this.
Adjust the secondary mirror until red dot is in centre of primary, then adjust primary until red dot disperses in middle of collamination tool, back to secondary and make sure it is in centre of primary.

When i view Jupiter, i can't quiet get a good clear image, slightly fuzzy, but can see the moons around it as stars.
With Saturn, it is a little fuzzy and although i can see the rings, i can't really see the individual rings.

I hope that explains things a little better and really do appreciate all the advice, especially if i am heading of in the wrong direction completely like it sounds like i could possibly be.

So was mainly hoping to get a better crisper cleaner and if possible, slightly larger image of planets.

Always appreciate any advice.
Thanks.
Peter.
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Old 25-04-2019, 09:32 AM
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Fair point Brian, maybe the OP should consider mounting the tube on an EQ6?

Optically, it shouldn’t be a challenge, it’s just the tracking and smoothness of motion. It’s something the OP should test.

FWIW, while the holy grail, of all theories solar system, favours scopes with small obstructions (or none at all), I’m very happy with my planetary images from my SCTs.

Add to that, the finest planetary images I’ve seen generally come from large SCTs and other scopes with significant obstructions.

There was a post a few years back over the other side where a chap had crunched the numbers and found that the obstruction of the average SCT resulted in contrast enhancement of certain feature scales in Jupiter’s atmosphere...
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Old 25-04-2019, 09:42 AM
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Quote:
Originally Posted by bluesilver View Post
The only issue with planets that are letting me down and this could just be my setup / collimation, i am using the laser collimation tool for this.
Adjust the secondary mirror until red dot is in centre of primary, then adjust primary until red dot disperses in middle of collamination tool, back to secondary and make sure it is in centre of primary.

When i view Jupiter, i can't quiet get a good clear image, slightly fuzzy, but can see the moons around it as stars.
With Saturn, it is a little fuzzy and although i can see the rings, i can't really see the individual rings.

I hope that explains things a little better and really do appreciate all the advice, especially if i am heading of in the wrong direction completely like it sounds like i could possibly be.

So was mainly hoping to get a better crisper cleaner and if possible, slightly larger image of planets.
I wouldn’t rule out collimation errors, high magnification planetary will really show up any errors. Have you tried barlowing your laser?

Other than that, it sounds like fickle seeing. Up here in Brisbane, the nights with good enough seeing for nicely detailed planets are few and far between. Unfortunately, forecasting of seeing is somewhat haphazard.

The only way to ascertain if this is contributing is to check regularly, both on the same night and on multiple nights. Some nights will be better than others and on those nights more details will be available. Dial up the magnification and see what happens. If all it does is to increase the size of the blurry view, then the seeing isn’t up to it!
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Old 25-04-2019, 01:39 PM
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Yes its colimation .

Forget the laser ! , use it to get it close ( that's all they are good for ) , then use a star at about 3-4th mag at high powers 500x Plus in the center of the FOV ( hard with a Dob but not impossible ) to tweak the screws until the slightly de-focused donut shape is centred ! .

It's easier with 2 people , one looking at the image and keeping it central and one turning the colimation screws .

Do a Google as there are heaps of good vidieo's out there .

This is my C9.25 getting close after dis-assembly for cleaning using a small ball bearing reflecting sunlight ( artificial star ) in a tree about 1km away hence the deformaties seen , heat haze .

Brian .
Quote:
Originally Posted by bluesilver View Post
Hi, I appreciate all the advice and answers, exactly what i am looking for.
I don't really have any clubs around here close by, best one is at the other end of the state, about 3/12 hours drive unfortunately.

I do have good clear unpolluted skies here, nearest street lights / town lights are a good few kilometres away and i live on a 200 acre farm property.

So from the sounds of things so far, as a few have advised me, my eye pieces i am trying to use for DSO's are not right, i need wider ones, around the 25 mm.
That helps explain a lot to start with.

The only issue with planets that are letting me down and this could just be my setup / collimation, i am using the laser collimation tool for this.
Adjust the secondary mirror until red dot is in centre of primary, then adjust primary until red dot disperses in middle of collamination tool, back to secondary and make sure it is in centre of primary.

When i view Jupiter, i can't quiet get a good clear image, slightly fuzzy, but can see the moons around it as stars.
With Saturn, it is a little fuzzy and although i can see the rings, i can't really see the individual rings.

I hope that explains things a little better and really do appreciate all the advice, especially if i am heading of in the wrong direction completely like it sounds like i could possibly be.

So was mainly hoping to get a better crisper cleaner and if possible, slightly larger image of planets.

Always appreciate any advice.
Thanks.
Peter.
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Old 25-04-2019, 04:44 PM
bluesilver (Peter)
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Yes, after reviewing the replies it appears that is the answer.
I have a GSo Collimator and thought about upgrading to a fairpoint one.

But from what you just mentioned, they are only to get you close.
I will have to do a bit of a search on videos to find out about the refining part of it.
When you say tweak the screws, are you referring to the primary ones or the secondary ones?
I am guessing the primary? also guessing tricky by yourself.

I have had a few looks at you picture, but will need to do a bit more research to find out exactly what i am looking at unfortunately.


I have always collimated it before i take it outside, and now after reading all this, i think this is another part of my issue.
As i have it on a trolley with solid caster wheels, when wheeling it out, it does vibrate and shake the scope a bit with the small bumps and joins in the concrete. I am guessing this isn't helping my collimation by the time i get it to my viewing spot and then lift it over to it, but it shouldn't move the mirrors that much should it?

But i have noticed sometimes when i have done the collimation, taken the laser out, then put it back in, that it has changed minutely, as if the laser it out a tad.

But will do a bit more video research on the fine tuning side of things.

Appreciated heaps.
Peter.

Last edited by bluesilver; 25-04-2019 at 05:27 PM.
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Old 25-04-2019, 06:20 PM
GodsPetMonkey
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Quote:
Originally Posted by brian nordstrom View Post
At 500x where a good 10 inch is still not breaking a sweat , the Dob mount has run it's race and it gets hard fast really fast , true my friend .
On a traditional nudge-mount Dob I'd agree that really high magnifications are an exercise in frustration. But bluesilver says he has the goto 10", which assuming has been turned on and set up correctly should allow several minutes of centered viewing (my 8" goto dob certainly does!). Even when your target drifts too far, the handcontroller makes it it easy to bring it back.

Won't be as good as a decent EQ mount, but for visual it'll do the job perfectly well. If bluesilver hadn't said their Dob was goto, getting a goto mount for the Mak would have been a pretty big plus!

Quote:
Originally Posted by bluesilver View Post
I do have good clear unpolluted skies here, nearest street lights / town lights are a good few kilometres away and i live on a 200 acre farm property.
As a suburban dweller, that is a problem I'd love to have!

Quote:
Originally Posted by bluesilver View Post
So from the sounds of things so far, as a few have advised me, my eye pieces i am trying to use for DSO's are not right, i need wider ones, around the 25 mm.
That helps explain a lot to start with.
A think a good widefield eyepiece would be an excellent addition to your kit. How wide? Well, that depends on what you want to look at. If you google telescope FOV you will find a few tools that will let you visualise the view you will get with different eyepieces on your scope on well known objects - second best thing to being able to try one yourself (which is hard if you don't have any clubs nearby).

IMHO, your current kit-25mm is enough to get you started, though it is what it is. Given you have a 10mm Delos, you obviously are not afraid of spending up to get quality eyepieces (and like eye relief or wear glasses?). Use what you have while you save up for a nice wide eyepiece.

Quote:
Originally Posted by bluesilver View Post
But from what you just mentioned, they are only to get you close.
I will have to do a bit of a search on videos to find out about the refining part of it.
When you say tweak the screws, are you referring to the primary ones or the secondary ones?
I am guessing the primary? also guessing tricky by yourself.
As Brian says, collimation tools will only ever get you close to collimated. Neither laser nor cheshire will get you spot on! To me the big plus with lasers is that once you are practiced they are pretty quick and remain easy to use in the dark, but cheshire's have their simplicity and it is good to be able to check against yourself.

But also be wary of the spending so much time and effort chasing the perfect collimation. Obviously your tools are not getting you close enough on their own, so go for the defocused star method to further tweak, but know you can end up spending a lot of time and effort chasing your tail (and that chews up valuable viewing time!).

The primary is probably what you need to adjust (unless you start way off!). I'd suggest getting some Bob's Knobs if you haven't already - fumbling allan keys in the dark is NOT fun.

Last edited by GodsPetMonkey; 25-04-2019 at 06:37 PM.
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Old 25-04-2019, 10:23 PM
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The SW 10" goto dobs fortunately already come with thumb screws/knobs for both the collimating and locking screws for the primary.

On the unfortunate side, collimating newts take a bit to get your head around initially, but once you get it sorted what's happening it's not that bad.

Rolling your dob out on a trolley over bumps wouldn't hurt your collimation, unless your running it out like a Jamaican bobsled team practicing on a dirt road or trying to see how much air you can get when you hit a bump.

On the topic of laser collimators... These in themselves actually have their own collimation grub screws to align the laser, and seem to not be accurately aligned when they're purchased. Especially the generic type laser collimator that is widely available.

This link will help you collimate your collimator... http://www.stark-labs.com/craig/llcc/llcc.html

So that may be why it seems to have changed when you re-insert the laser.

I use both a cheshire and laser. The cheshire I use to make sure my secondary is positioned centrally, and also to confirm my laser has done a satisfactory job.

Cheshire and Laser collimators aside. Ergh... both of these will give you different/disagreeing results if you try to cross reference them unless you square up your focuser first. Your SW Crayford Focuser has it's own alignment locking and grub screws so you can square up your focuser with the tube.

The good thing is it's not necessary to ensure your focuser is absolutely square. It just does your head in when you can't figure out why your secondary mirrors position looks so out of place when you sight through a cheshire after collimating with a laser. I squared mine because I'm pedantic about my cheshire & Laser results matching, not because it's required.
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Old 26-04-2019, 08:29 AM
bluesilver (Peter)
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Thanks again for all the replies and advice.
After reading through them a few times, it is all starting to make sense now.
Yes it is a goto Dobsonian, so that will make things easier.
Will give the star collimation a go next time it is a cloud free night here.

Appreciate all the advice.
Thanks.
Peter.
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Old 26-04-2019, 12:04 PM
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Some good advice here regarding scopes and collimation but the limitation on planetary viewing is always going to be the atmospheric seeing. Even with the best planetary scope there will be some nights where you can't see much on jupiter. A 12 or 16" won't help (except you might get a bit more colour in the mush.) Those perfect nights when you can rack up the magnification and see great detail are few and far between unfortunately. Collimate as well as you can, let it cool down well , view when the planet is as high as possible, and then add a measure of patience until you find those great nights.
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Old 26-04-2019, 12:38 PM
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Thumbs up

Totally agree. Patience and persistence are the keys.


Quote:
Originally Posted by Rigel003 View Post
Some good advice here regarding scopes and collimation but the limitation on planetary viewing is always going to be the atmospheric seeing. Even with the best planetary scope there will be some nights where you can't see much on jupiter. A 12 or 16" won't help (except you might get a bit more colour in the mush.) Those perfect nights when you can rack up the magnification and see great detail are few and far between unfortunately. Collimate as well as you can, let it cool down well , view when the planet is as high as possible, and then add a measure of patience until you find those great nights.
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Old 26-04-2019, 12:46 PM
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Atmos (Colin)
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My second best views (absolute detail) of Jupiter have been through a 4" refractor under pretty darn good seeing. This was bested briefly by a 32" dob with a filter; although the 4" showed more detail overall I saw glimpses of detail within the equatorial bands with the 32" that I've never come close to seeing with a 4".
I've had some really nice views with my Mewlon 250 but never had the seeing while I've had it out to support beating what I've had with the 4".

My point being that the three most important aspects of planetary viewing are good optics, excellent collimation and good seeing. On one night my 12" dob almost approached what I saw detail wise in the 4". The larger aperture helped make the details easier to see but the seeing at the time didn't support the fine details. Under equal seeing conditions I know that my 12" dob would have bested my 4" refractor in every respect. My 12" dob on one night threw up better Jupiter images than my Mewlon 250 has as of yet but I know that's all to do with the seeing conditions I've been observing under.

So, making sure your mirror has cooled and getting the collimation correct would be your first port of call to getting better planetary views.
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Old 06-05-2019, 09:55 AM
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Sorry if i missed this in the thread above but I didnt see it asked. Do you have a feather touch type focuser for fine adjustments? A lot of factors mentioned all come into play and many change during a viewing session so it can be a juggling act to chase optimal focus/viewing pleasure. Overhead a target is separated from you by the smallest amount of atmosphere whereas at the horizon is considerably more, so atmospheric thickness and conditions will change greatly during a session. Your scope OTA has its own internal thermal effects coming into play, and while a cool down period stabilises the ota a lot its not a matter of it stabilising to a fixed level where it hold that without change. Local changes in temperature and humidity means the ota can be absorbing and radianting heat energy as well as expanding/contracting too. The amount is minute, but its a factor. Your eye pieces likewise. Then there's your eyes. they constantly adjust to the low light they dont adjust to a set level and hold there, they wax and wan constantly. when you put your eye to the eyepiece and observe a bright target it can weaken your night vision slightly which takes longer to re-adjust again. same with a glance at a phone screen etc.

Everything comes into play even in tiny amounts but they all multiply to a noticable change in viewing quality at the eyepiece. No single answer will solve the problem but some coontribute more than others. I commonly find people think the big tube things is the important part of a telescope but its really the eyepieces that do the hard work with the photons, so people whoe rely on their supplied eyepieces are missing out on the potential of their gear, though in your case you have good eyepieces maybe not the best sizes for your ota. Start from the base up, make sure the mount is stable and firm so it doesn't pick up vibrations from the ground and amplify them to the eyepiece. Check things tat should be tight are tight and things that things that can move are clean and frictionless as you can get them. Periodically during a session inspect your optics for signs of fogging indicating you may need to look at methods to insulate to help prevent condensation. Specks of dust rarely do anything much to viewing so dont be too worried about those but also dont let dust build up either. learn to colimate by sight on a star, many of thoes laser collimators themselves are not collimated and only really get you to a ball park. a 10:1 ratio focuser will greatly help you get to a sharp image for your optics , the optics themselves (refracting lens and reflecting mirrors) are all made differently which is reflected in their pricepoints, along with coatings to reduce internal reflections and loss of photons all come into play. many people think big magnification numbers is all that matters when its pretty much irrelevant completely. Spending the extra dollars up front pays off in viewing pleasure for years to come especially when you are using near the limit of the optics. Every layer of glass or mirror a photon has to encounter to reach your eye reduces its energy (ie a loss) so anything there you can improve or remove can help matters. Avoid looking at your phone or bright things during your session to allow your eyes to adapt as best they can to the darkness. Also be patient and calm at the eyepiece, especially on those fainter targets as the eye will spend time adjusting to that specific view and it will become sharper to you over a few minutes. best to adjust fine focus when you are ready to view to account for atmospheric changes. There's only so much money that can be thrown at the problem and we all want to get closer and sharper with our views but there are practical limits. I don't know how many rings of saturn you should be able to see but the cassini division at least should be crisp to you. its very likely the upper atmosphere where you are is moving fast and causing the watery wobble you see... not much you can do in that case except view when your target transits its highest point in the sky.
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Old 07-05-2019, 03:11 PM
bluesilver (Peter)
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Thanks for the replies.
Got the mirrors all lined back up again using the Cheshire eye piece tool.
Thought i would pop the laser that is collimated in to have a look and the laser was tell me things were way off, so putting that down to a very bad laser possibly.

One interesting thing i did find and was hoping someone might be able to advise me on.

Got secondary mirror nice and square and centred to eyepiece holder.
Got the secondary mirror spot on lined up with the primary mirror so that i could see all the primary mirror clips nicely evenly through the eye piece holder.
Lined primary up so that the centre is spot on with the cross hairs and in the centre.

The only thing oi found was that no matter what i do, ( moving the secondary in or out, tilt left or right ) i can;t get the reflection of the bottom of the eye piece holder to to be centre in the mirror reflection.
It of always off a little.
Everything else is spot on right using the Cheshire eye piece.
It is as if the eyepiece holder need slightly packing up on one side.
I have only noticed this just now when trying to get everything spot on.
Never noticed it before as i was just mainly using the laser.

Dose this sound right? or a slight manufacturing error from the factory when installed?

Any advice is appreciated.
Thanks.
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