Shimonu

1 minute ago, Jjmorris90 said:

I don't know what I was expecting lol. Shouldn't it be more centered? 

 

How can I get rid of the dust?

The point of the flat frame is to measure the uneven light across the sensor. The point is that these frames are then used to remove the dust artifacts you'll have in your picture so you don't have to remove the dust, because you're unlikely to remove all the dust everywhere and keep it clean. What is the result like when you have applied the flat frame?

This looks like a decemt flat frame to me, what are you expecting? It's showing the vignetting and dust particles causing the donuts.

2 hours ago, newbie alert said:

When tuning the backlash out did you do it with the mount loaded or unloaded?

I did it unloaded, thinking it would be easier to feel any backlash. But I suppose binding could occur if the load is different?

I've been working on the backlash on my SW NEQ6 to improve my guiding which I did quite successfully, I got quite stable guiding under 1" which I was very happy with. However as I reached a meridian flip them mount started slewing and suddenly locked up on the DEC-axis. I was surprised as I tested the axis before at home and verified it running fine. The only thing I could think of was the temperature difference or maybe I didn't really run through the whole range of the axis.

So does temperature affect the backlash in any significant way?

What is a good way to make sure the backlash is as tight as it can get? I read that you should ideally find the tightest spot and adjust the backlash there but is there a good way of doing that? Turn a quarter and repeatedly feel for where it gets tighter and then looser but is it really that noticable?

Thanks

I'm looking at configuring Ekos to autofocus on filter change but I'm not understanding this "lock filter" option. It sounds to me like I would choose another filter to focus the one I'm going to use.

From the indi library website:

Quote

You can lock a specific filter within the filter wheel to be utilized whenever the autofocus process is invoked. Usually, the user should select the Clear/Luminescence filter for this purpose so that Ekos always uses the same filter to perform the autofocus process.

But isn't the whole point that the focus point can be different for different filters?

Just watched a bit of Cuiv and saw his video on the filter lottery. Manufacturers do not appear to have good quality control when it comes to the bandpass, sometimes it can be incorrectly offset and you're not getting the correct bandpass. There doesn't appear to be an easy way of finding out either, unless you do what Cuiv did and sent the filter to a lab for testing.

I don't know if this is the case for you but I certainly wish I had known that before I bought my new narrowband filters.

1 hour ago, alacant said:

I know of no Newtonian which works for astrophotography (well) out of the box. 

Maybe TS can help within your budget?

Or how about the SW 130pds? 650mm. It can be made skyworthy -i.e. made to retain collimation- in around an hour.

Don't forget the extra for the coma corrector.

Cheers

Maybe I'll do more research on the UNC, if the springs are what I should fix first then that seems like a minor thing I could live with. I just want to feel that I can at least attach my equipment for a few sessions and get a good baseline before I start doing bigger modifications and taking it apart. I'm sure I'm handy enough and capable but I like getting comfortable and knowing the stuff first.

Moving up to 100mm+ aperture refractors just feels too expensive at the moment.

10 minutes ago, alacant said:

Yes. That's where the focus podition should be, around 6cm above the top of the focuser. But why the massive 7cm secondary? If you don't need to cover full frame, specify 58mm or 63mm.

I believe though that even the UNC retains the toy springs. And still only 3 of them. Easy to fix of course, but if you're paying €high...

 

So stepping back and instead of looking at my requirements. Is there a recommended scope if I want something around 600-700 mm focal length and 130-150 mm aperture that is well built, pleasant to use and gives good results out of the box? And let's say the budget goes up to around €1000

12 minutes ago, alacant said:

Hi

Look carefully at which model it is. AFAIK, there is only one type available at sensible prices. The one we tried had a metal tube and of good quality, but the spider for the secondary was buried quite a way from the open end of the tube, was un-reinforced and the tube dented as you tightened the spider thumb screws. It had an unnecessarily large secondary throwing the focus position to a position way out from the tube, even with a dslr. It really was unworkable and un-balancable, as half of the light path came after the secondary. Here's an example with an eyepiece at focus. A camera is not going to be much better. We came to the conclusion that if you wanted a sensible 150 f4, you'd have to specify an ONTC yourself with the secondary further up the tube, as there seem to be no other versions other than the GSO/TS reasonably priced.

If you find otherwise, please post, as the idea of something as light and as fast as this appeals:)

 

Wow! I had never considered the position of the secondary and now that you point it out it looks really far back and strange.

This UNC would be much better then? https://www.teleskop-express.de/shop/product_info.php/info/p5881_TS-Optics-6--f-4-UNC-Newtonian-Telescope---Carbon-Tube---made-in-Germany.html
It's certainly more expensive but that's less important in my mind if it works well and is more pleasant to use.

5 hours ago, alacant said:

Don't know which telescope you have (all f4s are nice), but it will almost certainly need to be dismantled. Whilst it's apart, replace the springs with ones which are up to the task. 8", we use 1.6mm wire. 6", 1.4mm etc. Include passive springs over the locking screws leaving the latter loose.

I'm currently looking at the TS Optics Photon 150/600. I'll likely ask more about disassembly if I get it, I'm sure it's easier once you have something in front of you to look at.

Regarding a carbon fiber tube, are the benefits the reduced weight and not having to refocus with temperature change? I'm wondering if it's really worth essentially double the price.

1 hour ago, alacant said:

If you have the primary fixed with silicone to prevent sideways and up and down motion, then no. This also has the advantage of the coillimation holding at all angles the telescope assumes during imaging. 

HTH

Is this possible to do with the scope assembled or will it need to be taken apart?

Fantastic help, I feel like I understand the steps of collimation better now and it certainly doesn't feel as daunting.

I always put my equipment in the car and go just 5-10 minutes away. Is it crazy to think the collimation would hold if done at home and then going out for a night?

I'm trying to convince myself that I wouldn't be too bothered with collimation of an f/4 newtonian even if it would be my first newtonian. I'm doing my best to read guides and understand the tools that are used but I'm getting somewhat confused. I've seen collimation cap, collimation eyepiece and cheshire. These all seem to be either a long or short tube with a hole in the center and an opening in the side(except for the collimation cap). Could someone please clarify what the differences between these are and how they are used?

I'm also seeing some confusing discussion on if the secondary should appear in the center or if it should have an offset, or maybe some shadow should be offset and this appears to be different depending on if it's a "fast" or "slow" scope. Is there a clear guide for how to align the secondary and which references to use? Does the manufacturer provide any collimation information(likely TS Optics in my case)?

How good of a collimation can you do at home that will then give you good stars? Some seem to feel that you always need to do a final star test.

That's a really nice version of Andromeda. I hope I can get one that good

14 minutes ago, Clarkey said:

The GPU is certainly a better corrector than the MPCC but at F5 the Baader should be ok. There are always plenty going second hand on Astro Buy And Sell so you could try it and resell if you aren't happy. I have both and the GPU is better on my F4 but at F5 there is not much in it. The GPU is quite fussy on distance to the sensor.

WRT the guiding, the scope you have have should be fine to guide the 750 FL. If you are not getting good enough results look at the mount. Both my SW mounts needed fettling before they were acceptable. They do suffer from backlash when not fully 'tuned'. You could go down the OAG route but at 750mm you don't need to.

Much appreciated. When you say the GPU is fussy, you mean even caliper measurements won't give you any guarantees, I'd likely need to fine tune it?

Currently I'm looking at the TS Optics 6" f5. I see you have the f4, did you ever consider the f5? As far as framing goes it doesn't seem like you miss out on any targets. My thinking for the f5 was that the collimation would be easier. As it's my first newton I figured it would be a gentler introduction for me.

Birthday is always a good excuse to treat yourself to some new gear, right?

I've had my eyes on a Newton and a 150/750 for AP which seems like a good balance for me. Talking to the owner of astro-art he recommended the Lacerta coma corrector, as I understand it it's a GPU-design? However I'm not quite sure what that means. The alternative would be the somewhat cheaper Baader MPCC Mark III. What are the differences here?

I've also thought about the guiding requirements. I'm currently getting around 0.8" - 1.4" and I feel like I would need to improve that as my pixel resolution is going from about 2.2" to 1.3". Am I right in that my guiding error should not greatly exceed my pixel resolution? The options I've seen here is:

1. Upgrade my guide scope to a better quality and maybe higher focal length.
2. Get an off-axis guider.
3. Use my Z73 on top of the newton as a guider.

I mostly feel like option 2 and 3 are the most interesting. There's also the possibility that my mount is simply too worn and needs an upgrade or replacement.

Otherwise, going from a refractor to reflector I'm thinking I'll have to manage collimation so I know some thumbscrews for the secondary is always encouraged. I have a laser collimator which I'll see if it works for me.

52 minutes ago, alacant said:

Hi

Really? Kstars has the best graphics I've found on any planetarium. maybe you don't have any overlay set? You can use the NSEW mount controls to centre your camera accurately anywhere in the sky. 

Instead of 'Slew to Target',  centre your desired field of view then in the Align module, check 'Sync' instead. It will show you exactly where you are aiming and the camera's field of view no matter which orientation you set.

Cheers and HTH

Yes, I'm realizing I don't have the overlay now. I don't understand why it isn't enabled by default? I know I've downloaded the images but then I could just never find how they are actually used. That's certainly going to make it easier.

14 minutes ago, teoria_del_big_bang said:

I know exactly what you mean and whether its the right way or not I have been slewing to the target and plate solving to sync the mount to where it is on the planetarium and then taking say a 30 sec frame in Ha enough to see the nebula and then 1st rotate the camera (originally by hand but now I have a rotator 🙂 ) to get my desired angle, then take another image and then if I think I need to move over a bit then just select a star somewhere near where I want the centre to be and slew there. Usually doing this I get my framing 1st time (unless my OCD kicks in and I want a little bit more then I can end up fiddling about for ages till I slap myself 🙂 ). Then copy and store one frame somewhere that I know is my best framing for the setup I have and rename it appropriately so I can use that in future. Once I have this frame for a target you then do not even have to look at the planetarium just tell EKOS to slew to the saved image and it will first platesolve the stored image then slew to that target and do its usual plate-solving and further small slews till its pointing at the same place in the sky as the image (within a tolerance set in EKOS).
Normally plenty of stars to pick but if it's an area lacking in stars then more of an issue.

I assume you are talking about the KStars planetarium ?
You can have pictures of most of the nebulas but you have to select them under View/HiPS All Sky Overlay

I admit that some of the pictures aren't the quality of Stellarium but they are good enough to get you pointing where you want pretty quickly.

 

Steve

Oh wow! That's more than sufficient for framing! It's not some plugin or extension you have to download that I've missed? I'll have to check that out!

What about if you want some custom framing that doesn't just match the center position of some object? I recently shot NGC7000 and if you want to get the cygnus wall and the pelican for example, there's not just some point you can slew to, you would have to guess and take a lot of test exposures while slewing aimlessly. I don't feel that the planetarium is very helpful as it doesn't show the nebulae outlines or have any pictures.

The point of flats is to capture the vignetting and dust motes, things that affect the distribution of light on the sensor. It's not expected to be flat, it's supposed to make your image more flat as an end result.

How does it look when you use it in your stacking?

That nebulosity in the top-right, or bottom-left in the second picture, looks very interesting. I'm sure it looks spectacular from inside the galaxy.

Did you tighten the lock screw for the focuser? Not that I've ever experienced any slippage though. In my experience I've had to look quite closely at the spikes to find the center, they're not sharp themselves. If you're using the built-in mask I've heard claims that it's not really the best performing mask and I'd say there is some merit to that.

How do you approach the acquisition balance between filters? Do you analyze the target and which colours/gases it consists of and focus your acquisition on filters that should have most signal?

My first real target with LRGB mono was the Crescent nebula I experienced that using less blue and luminance for example in the stacking would give me a nicer red. If I included an event amount of data on all filters then I felt the image was almost washed out and white/grey in the nebulosity while I expected it to bring out the nebulosity even more.

Perhaps my issue is more of a stacking and post-processing problem but I suppose you could avoid it directly by choosing to balance with the filters.

3 minutes ago, StuartT said:

I wasn't really thinking about the calibration frames. I assume those are unaffected by a meridian flip. 

What I was asking was whether or not I have to rotate the images from the second night through 180 degrees so they match up with the images from the first night. But it sounds like Astro Pixel Processor is clever enough to do that on its own

 

The calibration frames are not affected by meridian flips but your flats might not be identical between sessions.

APP will figure it out. I think the multi-session option in APP is mostly so you can apply your calibration frames per session.