Roog

Thanks everyone, for your helpful advice and observations, next time I am out I will check the secondary as this seems to be the main target and I shall be more observant to minimise the risk of dewing up my eyepieces and telrad. 

19 hours ago, Pixies said:

I find that the screen of the Telrad finder acts like a dew-canary

Ah yes I have noticed this too.

Many thanks for all of your advice, I will seek to find out if it is the secondary mirror, but it does seem the most likely issue from all of your comments. I will be on the look out for an exercise mat too.

Thank you for your thoughts @wulfrun I am just jumping to conclusions really, but next time I will do the torch trick with the secondary mirror. 
my Dob is a metal tube type so I assume that this might offer some protection but I have seen a few set ups using heater blankets wrapped around the tube and the secondary mirror support and I wondered if this was what I need.

Having got my first telescope, a 10” dobsonian back in September the majority of my viewing in the UK has been in cold conditions, it’s tough but it’s got to be done if only to catch my first proper glimpses of Orion’s beauty. However I have begun to notice that whilst every thing starts off ok, after say 30 to 40 mins I find it harder to bring stars into sharp focus. I have become quite adept at collimating my scope in the field so I don’t think it’s this, could this be due to build up of dew? 
Peering into the main mirror it isn’t obvious to me if it is dew.

Any ideas welcomed, and if it is dew, is there a popular kit of bits to deal with this for my 10” Dob? 
 

many thanks Paul

On 20/01/2022 at 22:37, LostInTime said:

You can buy 'suitcase' ramps, intended for wheelchairs, which you fold up when not in use. They stow away easily and come in different specs. depending on size and the weight they need to cope with.

Absolutely @LostInTime I managed to find one of these on Gumtree and it works well, that is until in manage to finish my back door, one step lift! Development currently in progress.

On 13/11/2021 at 18:51, Roog said:

Not sure how far it will go on the tool battery, but 4 or 5 hundred metres would probably be fine for me.

Update on battery powered Dob trolley.

It is a source of amusement to me that it is still on its first charge since Nov 2021, and spare battery hasen't been touched.  I have also decided that going backwards, like a forklift truck, whilst very manoeuvrable is not especially intuitive to me so I may 'flip' the steering handle the right way around to travel single wheel first.  

17 hours ago, Mike Q said:

I have given a lot of consideration to getting an appliance dolly and using that to transport my dob.  A couple ratchet straps in the right places and it won't move

I have one of these too, three holes drilled where the dobs feet can lodge and one in the middle for the pivot bolt to poke through, I guess you could use a few clips to hold the dolly onto the bottom of the scope base when lifting it about.  

Thank you for clearing this up for me. It seems that for what you are saying, whilst mono plus filter wheel may return the optimal results for your set up, in practice the difference may not be significant for a modest armature setup? 

Following on from my, how to get started in imaging type thread, I have noticed that people sometimes start off using a colour camera but quite often migrate to mono with a motorised filter wheel.

My question is, does the imaging software deal with moving the filter wheel for you in synch with image capture? Or is it much more complicated than this?  

Thank you @edarteroh I am in total agreement with you, my biggest fear by far is in processing data. I am not at all comfortable with computer based applications, this is one of the the reasons why i opted for a visual rig.

As per my original post , I am itching to give astrophotograpy a go, I would like to give it my best shot without needing to win the lottery, I don't mind saving for some thing if the result is that I enjoy the experience. Equipment that can't gather reasonable images and software that i cannot fathom would be a terrible outcome.  

I am currently aiming  for a CEM 40 with a modest refractor, say 80mm, I need to look at the weight of all of the bits to see how close I get to the payload capacity of the mount, which I propose to consider very conservatively.

I shall return.

Thank you all for your advice, I appreciate the importance of a good mount and tripod, not to mention a firm surface on which to place it. I am naturally  a sceptic when it comes to performance specs, but I guess you have to start somewhere. 
 

2 hours ago, teoria_del_big_bang said:

A good explanation HERE

Steve

Thanks Steve, that’s the best explanation I have seen and explains why I have seen people talk about spacers and cameras!

Cheers @inFINNity Deck the app looks helpful, I can see me tinkering with that.

5 hours ago, iantaylor2uk said:

A William Optics 81 mm triplet is a good choice (I have the 81 GT IV). You will still need a flattener, you can either use a dedicated WO flattener/reducer (which will give you a focal length of about 380 mm) or a general purpose flattener (I use a Hotech 1x flattener, which gives a focal length of 478 mm). This gives good round stars right out to the edge of an APS-C sized sensor, and at 478 mm focal length, the field of view is 2.8 x 1.9 degrees, with a resolution of about 2.1" per pixel, so autoguiding should be pretty straightforward. A larger refractor will usually have a longer focal length, so a smaller field of view, which can be good for some targets, like galaxies. 

Hi @iantaylor2uk thank you for your help, the Williams optics is one on my list of APO’s to consider. Can I ask, what is a flattener, why do I need one and why does it affect the focal length?

9 minutes ago, Elp said:

If your polar alignment is good you can use the mounts in built sidereal rate to move with the rotation of the stars (earth) as long as the mount has motors built in or bundled with therefore unguided. I'd start from there.

When you decide to go down the autoguide route it'll empty your wallet pretty quick as you'll have to buy astro cameras and associated equipment of which you'd want a decent one so it can perform more than one duty. Then there's the technical issues you WILL face and have to overcome before you even get into a position to start imaging. If you want easy, an Asiair pro/plus makes the process so much easier though it's another purchase and you're tied to using ZWO cameras (or a supported dslr). There are cheaper options like a raspberry pi or pc but it depends on how much you want to lug around and setup.

Start simple. Once you reach a limit move onto something else then. You'll forever always be looking for the next upgrade with this hobby.

All that you say @Elpmakes sense, it seems to me a case of pitching my starting point at a place where I will be motivated to persist and not demotivated due to too many technical obstacles or limitations 

cheers Paul

13 hours ago, ONIKKINEN said:

I would point out a few things that came to mind. How quickly do you want to get results? What types of targets do you have in mind? How much do you want to tinker or "lose time" with the setup?

I image with a 200mm newtonian and a poor quality mount and its been mostly trouble the whole time, so i would advice against that. Newtonian with a good mount? Dont know, as i do not have a good mount yet but im hoping my upcoming AZ-EQ6 will be up to the task. But here's the thing: I want to image galaxies, most of which are dim and smaller than nebulae, do not benefit from light pollution blocking filters, and i want to do this kind of imaging quickly as i cannot control the weather. I am also not made of money so a newtonian was really the only option for me. Large aperture compared to price and a very convenient focal length that is not too large really fits my use case perfectly.

But if i had more money i would definitely want an APO in the 130mm and up range to do the same job. Also, if you are already considering the HEQ-5 which is a fair bit of money why not go for the bigger EQ6R-PRO? I really do hate my mount and wish that nobody would try to undermount their telescopes so if i had a time machine i would put almost all of my budget into the mount.

Thank you @ONIKKINEN, I see your point about having the time vs aperture, Vlaiv   Also made the same point but coming from the other direction, small can work if you can invest the time. It’s a bit of a balancing act isn’t it.

37 minutes ago, happy-kat said:

Also think about storage and setup location. A heavy mount, heavy telescope (refractors can be heavy) and guiding setup, cameras, cables and power can take a while to setup to take a first image if you don't have a permanent observatory. Some use more portable setups with small lightweight refractor or lens.

Yes, I am beginning to see that astrophotography requires a lot of commitment, lugging my Dob out through the house and down the kitchen step is a pain, but once out it is easy to get observing.

12 hours ago, Clarkey said:

At the end of the day, the better the mount the easier it will be. (Cheaper options work - but are a pain in backside). After that choose your scope based on what you want to image.

I think all of you have more or less said this, I like the idea of choosing a refractor this time, not least because I don’t currently own one, although the cost of a big one is a bit eye watering.
I note that a few of you have raised the thorny issue of my ‘Budget’, this is tricky for me, like many of us money is hard fought for, but, I don’t mind saving and forking out for something if I think it is worth it.
Similarly, as a competent electrical/electronics engineer with a good appreciation of small scale mechanics, I quite like making and refining things, I made a motorised portable alt/ az system for a TV satellite dish years ago, it needed a lot of care and understanding to work  but when it comes to a  tracking mount driven by a computer I would probably appreciate one that just works as I will be at the limit of my mental capacity just dealing with the process of Astrophotography.
Actually this raises another very important issue for me, that of guiding and imaging software, this really needs to be as intuitive as possible for me. I am not sure if my choice of mount influences this at all?

I can see that the choice of mount will influence the experience when tracking, It would be nice to be able to buy just one and be happy forever, but I fear I ask too much.

thanks again, I’m off to read up on what has been said already.

kind regards Paul

Hi @Stefek your story is familiar to me, I have already started to collect too many redundant bits and pieces of Astro gear due to my ignorance of the topic, reading around it helps a little but hearing other people’s experience is very helpful. 
 

I plan to arrange a proper chat with our family friend on the topic in the new year, it would be good to discuss my anxieties face to face and to get a feel for the limitations of going smaller rather than jumping in with big and expensive straightaway.

Thank you for all of your comments, I have a fair bit to digest and links to check out. I will do this and get back soon.

thanks again

19 minutes ago, vlaiv said:

Heq5 is more than capable of holding 80-100mm frac and image with it.

This is up to 2 hours from very light polluted area taken with 80mm triplet on Heq5:

Did not bother to process out satellite trails. Same image contains like dozen or so galaxies.

Here are few more shots with different cameras (again 80mm / heq5):

Thank you again @vlaiv your images and posts are very helpful.

12 minutes ago, vlaiv said:

Depends on what you want to achieve and how much money do you want to spend on getting there.

Used DSLR is really most cost effective way as far as camera goes. Are dedicated astronomy cameras better - yes, some models are, but they are also much more expensive.

With about 700mm of focal length you can get to the limit of what you can achieve in DSO as far as resolution goes. With ~3.8µm pixel size (most modern CMOS sensors have pixels that large) and 700mm of focal length you are already approaching upper limit of 1"/px.

130PDS and 150PDS are both good newtonian scopes for imaging.

APO triplet in range of 100-120mm of aperture is also excellent imaging scope.

Difference is in ease of use - newtonians need collimation and sometimes have some quirks that need to be addressed - like rigidity of OTA / mirror moving / light leaks and so on, while refractors are mostly trouble free and of course the price - good triplet APO will be more expensive than newtonian scope.

Mount will probably be most important thing in your imaging setup - so put the bulk of your budget there.

I totally agree with your points @vlaiv thank you for your advice. As far as budget is concerned I would, like most people prefer to pay no more than necessary, however I get very frustrated when I buy in at the lower end and end up buying twice.

if a smaller quality telescope can do the job, I would be happy.

Similarly, I have read a fair bit about the popular mounts made by Skywatcher HEQ5 and 6 R models, people like to tweak and tune them and they seem to offer good payload and yet I read threads which say they aren’t a patch on ioptron CEM60 and above, actually I think they were less complementary than that! 
i can see that the performance of the mount is very important to accurately tracking the target and quality of the final image, it is for this reason that I am especially concerned about getting this right. 

Good suggestion @happy-kat I will pay more attention in future.

I suppose given my limited experience using visual only observations I note that some targets are visible to the naked eye and thus viewable in my dobsonian. Even then some are very faint. I have to wonder how well stacking multiple images from a tiny 80mm scope will compare?

Hello fellow stargazers,

I seek your help in selecting the right telescope for me to image deep space objects with.

I am the happy owner of a 10” Dobson Ian with which I enjoy visual astronomy from my back garden, however the lovely people of this forum keep posting their images from their astrophotography rigs and I am getting the itch to give it a go. Madness? Quite possibly.

When I made my dobsonian purchase I did so with the knowledge that big is good and I accepted the potential issue of moving the thing about, but when it comes to choosing a telescope for astrophotography it is not so clear to me.

I trusted family friend has suggested that I select an 80mm triplet APO, of relatively short focal length, SLR imaging camera plus HEQ5 mount and modest tracking scope.
And yet I see that others aim for 100mm and 120mm aperture triplet APO’s with dedicated Astro cameras and even bigger mounts! (Yes this is going to be loads of money) 
So is an 80mm APO with modest focal length enough for a reasonable selection of deep space targets? 

Then I see the likes of Rory aka astrobiscuit promoting the use of a 150mm Newtonian and a well used pro SLR, this all seems so different to the little 80mm APO. Surely these are not equivalent in the astrophotography world?

Sorry, but just to add one more request, I would like to have the opportunity to use the rig for a bit of go-to visual astronomy from time to time for when the Dob is not in the mood to go out in the cold! Would an 80mm /100mm  or 120mm APO serve this function, please. 
 

I would be grateful for your thoughts please, If I could pop into a local telescope shop I would bug them with my daft questions too!

Kind regards Paul