How to Choose Affordable and Easy to Use Telescopes for DSO Imaging

[Chris]

This has taken a month to put together, so I'm really hoping it's good advice lol

 

Edited December 14, 2020 by Lockie

[Nugs]

As a complete novice, i found that really helpful Chris.

It would be really nice if the stock of telescopes was there so i can part with some money to get imaging. I was really considering the WO ZS61 or 73, but after your post, i could save some money to put to a dedicated CMOS astro camera.

This may be a naive question, but when using the FOV calculator in imaging mode, if a scope with camera fills the FOV for a given subject, if another target appears much smaller with the same scope and camera, can you incorporate a multiplier between camera and scope to fill the FOV?

TIA, and keep up the good work.

 

[rickwayne]

11 minutes ago, Nugs said:

This may be a naive question, but when using the FOV calculator in imaging mode, if a scope with camera fills the FOV for a given subject, if another target appears much smaller with the same scope and camera, can you incorporate a multiplier between camera and scope to fill the FOV?

This turns out not to work well in practice, at least for deep-sky objects. Such a multiplier (usually "Barlow" in astro) spreads the light cone out for more magnification, so that less impacts the sensor. A 2X Barlow effectively adds an "f-stop" to the scope, converting an f/4 into an f/5.6, a 5.6 into an 8, and so on.

In fact many -- maybe even most -- deep-sky heads do precisely the opposite, mounting a focal reducer that concentrates more of the image circle on a smaller area. Brighter, but less magnification.

 

Edited December 14, 2020 by rickwayne

[Nugs]

4 minutes ago, rickwayne said:

This turns out not to work well in practice, at least for deep-sky objects. Such a multiplier (usually "Barlow" in astro) spreads the light cone out for more magnification, so that less impacts the sensor. A 2X Barlow effectively adds an "f-stop" to the scope, converting an f/4 into an f/5.6, a 5.6 into an 8, and so on.

In fact many -- maybe even most -- deep-sky heads do precisely the opposite, mounting a focal reducer that concentrates more of the image circle on a smaller area. Brighter, but less magnification.

 

Thanks for the reply @rickwayne. Would you then crop/zoom in post processing to bring the target to fill the frame?

[RobertI]

Great video Chris, entertaining as always and your advice is spot on. 👍👍

[Chris]

1 hour ago, Nugs said:

As a complete novice, i found that really helpful Chris.

It would be really nice if the stock of telescopes was there so i can part with some money to get imaging. I was really considering the WO ZS61 or 73, but after your post, i could save some money to put to a dedicated CMOS astro camera.

This may be a naive question, but when using the FOV calculator in imaging mode, if a scope with camera fills the FOV for a given subject, if another target appears much smaller with the same scope and camera, can you incorporate a multiplier between camera and scope to fill the FOV?

TIA, and keep up the good work.

 

Great to hear it was helpful, Nugs, thanks  Rick beat me too it regarding Barlowing for imaging. It gets you closer but slows down the optics which isn't ideal. You can crop in a bit in post depending on your resolution. Cropping also happens to be handy for removing egg shaped stars from from the edges of the frame due to coma, and it also helps with stacking artefacts. I don't think I've ever shared a picture that hasn't been cropped come to think of it 😄

[Chris]

13 minutes ago, RobertI said:

Great video Chris, entertaining as always and your advice is spot on. 👍👍

Thanks Rob I appreciate that! It took a bit of work lol Although several days of that was trying to sort out a video rendering issues. 

Edited December 14, 2020 by Lockie

[RobertI]

10 hours ago, Lockie said:

Thanks Rob I appreciate that! It took a bit of work lol Although several days of that was trying to sort out a video rendering issues. 

Good to hear you’re thinking about a 102ED by the way. Would you go for the FPL51 or FPL53?

Edited December 15, 2020 by RobertI

[Chris]

14 hours ago, RobertI said:

Good to hear you’re thinking about a 102ED by the way. Would you go for the FPL51 or FPL53?

I would really like the FPL53 variant, but I am curious to see how acceptable (or not) the FPL51 variant would be, especially as the price is so compelling. It would be great if FLO sold a 102 f/7 ED doublet in this price range. I think the closest was the WO 103 f7 but that was a few hundred more than the FPL53 Altair/TS F/7's plus they don't seem to be available any more. Still FLO have added some very interesting scopes recently  

[RobertI]

4 minutes ago, Lockie said:

I would really like the FPL53 variant, but I am curious to see how acceptable (or not) the FPL51 variant would be, especially as the price is so compelling. It would be great if FLO sold a 102 f/7 ED doublet in this price range. I think the closest was the WO 103 f7 but that was a few hundred more than the FPL53 Altair/TS F/7's plus they don't seem to be available any more. Still FLO have added some very interesting scopes recently  

I think the FPL51 looks cracking value and would be a great buy. The only reason I didn't go for it was that I'd never owned an FPL53 and just had to scratch that itch!! I hope you go for it!

[DaveS]

A very comprehensive and erudite presentation.

[Chris]

51 minutes ago, DaveS said:

A very comprehensive and erudite presentation.

Cheers Dave! Ironically I had to Google the meaning of erudite lol but thanks!

[Jamgood]

Very good and informative video. 👍

My only issue with it was the music in the background was unnecessary. Sometimes your voice was muffled with it. I'm deaf in one ear though so it might just have been me. 

[Chris]

23 minutes ago, Jamgood said:

Very good and informative video. 👍

My only issue with it was the music in the background was unnecessary. Sometimes your voice was muffled with it. I'm deaf in one ear though so it might just have been me. 

Thanks. I've had one other person mention about the music. Would it be helpful if I uploaded a version without the backing music? It wouldn't take me too long to remove it and re upload. It sounds less polished without music but it would be clearer.  

[Jamgood]

2 minutes ago, Lockie said:

Thanks. I've had one other person mention about the music. Would it be helpful if I uploaded a version without the backing music? It wouldn't take me too long to remove it and re upload. It sounds less polished without music but it would be clearer.  

Personally, I think it's more a case of balance. There almost seems to be a phasing issue between your voice and the music. When the music gets louder at 4mins it gets worse. There's a clash of music volume and the speed of your talking.

I'd turn it down quite a bit and have it very light in the background. It would help.

[vlaiv]

Given that this is one of those topics to which everyone would have something to add or say - thanks for keeping it real.

Very nice selection of beginner imaging scopes given.

[happy-kat]

The bits covering the FOV comparing large telescopes versus much smaller like a camera lens is clear and is often not grasped as to why small telescopes get suggested.

I'm not a fan of music on factual videos as I didn't watch the videos because I wanted to listen to music.

 

[Chris]

1 hour ago, vlaiv said:

Given that this is one of those topics to which everyone would have something to add or say - thanks for keeping it real.

Very nice selection of beginner imaging scopes given.

Thanks vlaiv, it's such a contentious subject I'll admit I was slightly nervous about posting.

[Chris]

4 minutes ago, happy-kat said:

The bits covering the FOV comparing large telescopes versus much smaller like a camera lens is clear and is often not grasped as to why small telescopes get suggested.

I'm not a fan of music on factual videos as I didn't watch the videos because I wanted to listen to music.

 

lol well I tried to choose interesting music that fitted in with the clips 😁 tested a bunch of different styles before settling on the neo classcial vibe. I must have spent two days choosing, mixing and timing the music for this video.

I'll raise the music issue with my YT subscribers, and if it's a common theme about the music not being ideal then I'll change it. 

I've thought about just changing it without asking my subs, but it might come across that I'm trying to 'milk it' so I'd better ask. 

[Chris]

Ok I've put out the feelers with my subs:

https://www.youtube.com/c/DIYAstronomy/community?view_as=subscriber

[Chris]

On 16/12/2020 at 13:18, Jamgood said:

Personally, I think it's more a case of balance. There almost seems to be a phasing issue between your voice and the music. When the music gets louder at 4mins it gets worse. There's a clash of music volume and the speed of your talking.

I'd turn it down quite a bit and have it very light in the background. It would help.

I've carried out a poll over the last few days, and perhaps surprisingly only 17% of people voted for lower music volume on videos. 54% voted to keep it the same and 29% voted for no music what so ever. 

I personally agree that on this occasion there was a small portion of the video at 4 minutes where the music was a bit too loud, but I'll respect the poll and leave it as is. 

I appreciate the feedback though

 

 

Edited December 19, 2020 by Lockie

[Sp@ce_d]

Hi Chris I’m just revisiting this thread after I had an initial look when you first posted. Interesting the music has come up as it’s what stopped me watching the whole thing.  I see you’ve done a poll & fair enough on those results but maybe I can throw some observations in the mix that may help?

 As a viewer I want to concentrate on what you are showing me but more importantly what you are telling me as it is informational. I want to learn something so concentration is key. Now, why did I feel anxious, distracted & unable to continue?  Its not so much the volume balance as it is the focus point. To me there’s a fight going on for the attention of my ears between the voice & the lead lines in the music. As a musician I’m plagued by this so probably hypersensitive but it will affect others subconsciously. When I hear music my brains breaking it down into the components automatically! So the choice of “background” music regardless of genre.. we all have different tastes anyway.. shouldn’t compete for attention with your voice. As much as we love listening to music in this case we don’t really want it getting our attention, it almost has to be boring & uneventfully flowing. No Lead lines, dramatic changes to distract & compete but pleasantly carrying your voice. I’m no expert in mixing voiceovers, I did attention seeking listen to me stuff so take this with a pinch of salt mate 😀 Plus my ears are well worn from the long gone days of playing with no ear protectors. Anyway, feel free to ask.. or ignore my ramblings mate.. here if I can help 

[Chris]

On 19/12/2020 at 13:18, Sp@ce_d said:

Hi Chris I’m just revisiting this thread after I had an initial look when you first posted. Interesting the music has come up as it’s what stopped me watching the whole thing.  I see you’ve done a poll & fair enough on those results but maybe I can throw some observations in the mix that may help?

 As a viewer I want to concentrate on what you are showing me but more importantly what you are telling me as it is informational. I want to learn something so concentration is key. Now, why did I feel anxious, distracted & unable to continue?  Its not so much the volume balance as it is the focus point. To me there’s a fight going on for the attention of my ears between the voice & the lead lines in the music. As a musician I’m plagued by this so probably hypersensitive but it will affect others subconsciously. When I hear music my brains breaking it down into the components automatically! So the choice of “background” music regardless of genre.. we all have different tastes anyway.. shouldn’t compete for attention with your voice. As much as we love listening to music in this case we don’t really want it getting our attention, it almost has to be boring & uneventfully flowing. No Lead lines, dramatic changes to distract & compete but pleasantly carrying your voice. I’m no expert in mixing voiceovers, I did attention seeking listen to me stuff so take this with a pinch of salt mate 😀 Plus my ears are well worn from the long gone days of playing with no ear protectors. Anyway, feel free to ask.. or ignore my ramblings mate.. here if I can help 

Noted. I was trying the opposite approach in a way i.e finding music that was interesting and fitted in with the subject (I tried various tracks before settling on these). The reason I was trying to find interesting music was in case my ranting wore thin lol