Explore Scientific 92/100 or APM

[Stardaze]

41 minutes ago, jetstream said:

Just look through one...

In comaparison to my 17E the Nikon 17 HW offers a more contrasted view on nebula which is quite a feat actually. The Swan, through the 17HW is a stunning stunning sight, filtered or not.

Thing is you get both a 17mmm and 14mm for the huge price... I bought mine directly from Japan when our dollar was more friendly to the Yen and did not pay near the quoted price in this thread.

And yet! the 20mm Lunt can hold its own in this crowd...

Probably best I don't... I've only just remortgaged 

13 minutes ago, John said:

@Stardaze there you go - you start a thread on the merits of £200-£300 eyepieces and end up getting recommended £1000 ones !

As Gerry / @jetstream says though - your original shortlist are hardly shabby in any way and will show fabulous views

 

Always the way, huh! Good to have things to aspire towards. I'm going to order the APM 13 next month and the 20 when it's back in stock. I'll buy a bandmate O-III too but want some longer binoculars for hopefully getting away still at the end of Aug if we can. I think the trick is really the secondhand market, but being prepared to wait for the right items. This coming year sadly, might see a bit coming up.

Edited June 12, 2020 by Stardaze

[Don Pensack]

2 hours ago, Stardaze said:

Probably best I don't... I've only just remortgaged 

Always the way, huh! Good to have things to aspire towards. I'm going to order the APM 13 next month and the 20 when it's back in stock. I'll buy a bandmate O-III too but want some longer binoculars for hopefully getting away still at the end of Aug if we can. I think the trick is really the secondhand market, but being prepared to wait for the right items. This coming year sadly, might see a bit coming up.

A couple points:

1) If buying used, avoid the TeleVue filters called BandMate.  You want the BandMate II, the later ones made by Astronomik.  Much better bandwidths and performance.

2) if you use a Paracorr coma corrector in a dob, the lowest possible setting is still not optimum for the Nikon HW 17.  They left a long length of filter threads on that one, and it simply cannot get close enough to the lens for optimum coma correction.  It's pretty close, though, and certainly no worse than the 31mm Nagler in the original Paracorr, which also could not achieve an optimized position.

3) APM is back in stock on the 20mm XWA HDC eyepieces.

[bomberbaz]

11 minutes ago, Don Pensack said:

A couple points:

1) If buying used, avoid the TeleVue filters called BandMate.  You want the BandMate II, the later ones made by Astronomik.  Much better bandwidths and performance.

2) if you use a Paracorr coma corrector in a dob, the lowest possible setting is still not optimum for the Nikon HW 17.  They left a long length of filter threads on that one, and it simply cannot get close enough to the lens for optimum coma correction.  It's pretty close, though, and certainly no worse than the 31mm Nagler in the original Paracorr, which also could not achieve an optimized position.

3) APM is back in stock on the 20mm XWA HDC eyepieces.

that's 3 @Don Pensack 🤣

.................................... I'll get me coat. 

Edited June 12, 2020 by bomberbaz

[Stardaze]

8 hours ago, Don Pensack said:

A couple points:

1) If buying used, avoid the TeleVue filters called BandMate.  You want the BandMate II, the later ones made by Astronomik.  Much better bandwidths and performance.

2) if you use a Paracorr coma corrector in a dob, the lowest possible setting is still not optimum for the Nikon HW 17.  They left a long length of filter threads on that one, and it simply cannot get close enough to the lens for optimum coma correction.  It's pretty close, though, and certainly no worse than the 31mm Nagler in the original Paracorr, which also could not achieve an optimized position.

3) APM is back in stock on the 20mm XWA HDC eyepieces.

Thanks Don. I’m a little dubious buying secondhand filters, I’ll buy new. 

[bomberbaz]

22 hours ago, jetstream said:

Just look through one...

In comaparison to my 17E the Nikon 17 HW offers a more contrasted view on nebula which is quite a feat actually. The Swan, through the 17HW is a stunning stunning sight, filtered or not.

Just thought I would add my best ever view of the Orion Nebula was through my 17mm Nikon HW with a basic O-III filter. It was at a fairly dark site although I remember that night there was quite a bit of moon to deal with. However the seeing and steadiness of the skies were close to the best I had ever experienced.

The eyepiece and scope combo gave 1.45 degree's of the sky and the nebula literally filled nearly the entire fov with filaments and structure simply jumping out at you but I have not since managed to emulate even at darker sites. 

An imaging friend I had with me took a look at the nebula also and he told me he was quite amazed at the detail it was yielding, almost as good as imaging. Praise indeed from a member of the imaging fraternity. 

[John]

Still pushing the £1K EP's ?

 

[Stardaze]

38 minutes ago, John said:

Still pushing the £1K EP's ?

 

Shall I go back and reapply for my remortgage? 🤣

Jokes aside, I can’t wait to see the Orion Nebula at xmas with a fairly decent setup. My first scope was ok but armed with quality filters and reasonable EP’s it really should be a totally new experience. 

[Timebandit]

1 hour ago, John said:

Still pushing the £1K EP's ?

 

 

1 hour ago, Stardaze said:

Shall I go back and reapply for my remortgage? 🤣

 

 

I am sure the Bank manager will most understanding , NOT 🙉🙊🙈 😣

 

There are some jolly good 92/100 Degree eyepiece's out there without taking a loan out to buy a Nikon 👍😁

 

 

[bomberbaz]

2 hours ago, John said:

Still pushing the £1K EP's ?

 

My share options are up in July 😂😂

[Stardaze]

I've ordered an APM 13 XWA earlier so look forward to seeing how that performs. 

[Stardaze]

The APM 13 arrived this morning and certainly is a nice chunk of glass. I’ll have to rethink my EP case when I add the 20 and probably 9. The 3 of them would  pretty much fill it!

Given it’s long length I found the 3 retaining grub Screws a bit of a faff to secure it into the focuser, seemed to not engage very well? Is there a better clip-lock 2” replacement available that secured a large EP better than the bresser standard?
 Edit: just seen this. Quite expensive but do they work well?

https://www.firstlightoptics.com/adapters/baader-clicklock-m68-clamp-for-hexafoc-focusers-bresser-omegon-and-explore-scientific.html

Edited June 20, 2020 by Stardaze

[Don Pensack]

1 hour ago, Stardaze said:

The APM 13 arrived this morning and certainly is a nice chunk of glass. I’ll have to rethink my EP case when I add the 20 and probably 9. The 3 of them would  pretty much fill it!

Given it’s long length I found the 3 retaining grub Screws a bit of a faff to secure it into the focuser, seemed to not engage very well? Is there a better clip-lock 2” replacement available that secured a large EP better than the bresser standard?
 Edit: just seen this. Quite expensive but do they work well?

https://www.firstlightoptics.com/adapters/baader-clicklock-m68-clamp-for-hexafoc-focusers-bresser-omegon-and-explore-scientific.html

Yes, that works well, but the issue is with the 3 screw binding.

One screw binds the eyepiece, but presses the eyepiece against one point on the other wall of the focuser, creating two pressure points 180° apart, so the eyepiece can wiggle back and forth 90° from that line.

Two screws press the eyepiece into contact with the focuser wall opposite, but the pressure points are 120 degrees apart and there is no plane to allow wiggle of the eyepiece in the focuser.

Three screws 120° apart makes no sense.  Two screws press the eyepiece into contact with the other wall of the focuser, but the 3rd screw presses the eyepiece away from contact with the wall at the very point it needs to be tightly pressed against that wall.

So if you have 3 screw binding, remove one of the screws and only use two screws to bind the eyepiece and it will be tighter.

If there is a brass split ring inside the focuser between the thumbscrews and the eyepiece, slide it around so both screws contact the brass ring.

 

[Stardaze]

4 hours ago, Don Pensack said:

Yes, that works well, but the issue is with the 3 screw binding.

One screw binds the eyepiece, but presses the eyepiece against one point on the other wall of the focuser, creating two pressure points 180° apart, so the eyepiece can wiggle back and forth 90° from that line.

Two screws press the eyepiece into contact with the focuser wall opposite, but the pressure points are 120 degrees apart and there is no plane to allow wiggle of the eyepiece in the focuser.

Three screws 120° apart makes no sense.  Two screws press the eyepiece into contact with the other wall of the focuser, but the 3rd screw presses the eyepiece away from contact with the wall at the very point it needs to be tightly pressed against that wall.

So if you have 3 screw binding, remove one of the screws and only use two screws to bind the eyepiece and it will be tighter.

If there is a brass split ring inside the focuser between the thumbscrews and the eyepiece, slide it around so both screws contact the brass ring.

 

Bingo! It’s a circular brass ring where on side doesn’t depress very well. I can see that two screws effectively would push the EP into the adjacent side which seems to secure better.

[Ricochet]

18 hours ago, Stardaze said:

The APM 13 arrived this morning and certainly is a nice chunk of glass. I’ll have to rethink my EP case when I add the 20 and probably 9. The 3 of them would  pretty much fill it!

Given it’s long length I found the 3 retaining grub Screws a bit of a faff to secure it into the focuser, seemed to not engage very well? Is there a better clip-lock 2” replacement available that secured a large EP better than the bresser standard?
 Edit: just seen this. Quite expensive but do they work well?

https://www.firstlightoptics.com/adapters/baader-clicklock-m68-clamp-for-hexafoc-focusers-bresser-omegon-and-explore-scientific.html

Yes, the click lock is excellent, whilst the standard Hexafoc 2" clamp is absolute garbage as it is too shallow. From memory it is something like 2mm of metal, and 8mm clamping ring and then another 2mm of metal. Any sort of undercut on an eyepiece or 1.25"-2" adaptor will result in the original clamp tilting the eyepiece and putting the system out of collimation. 

The only issue you might have is with the resulting focuser being a bit too long or a bit too short. Find the click lock page on Baader's website and there is an image that gives the optical path length for all the different click locks. You can then check at what distance your eyepieces focus (use the scale on the focuser) and, by measuring the height of the 2" clamp and the extension, deduce which combination allows you to focus. With my 8", I removed the extension piece as well as the original clamp. This is a little shorter than the original, and the focuser is racked almost all the way out to focus, plus the only 2" eyepiece I use is lifted out of the clamp by parfocalising rings so that it focuses at the same point as my XWs when they are in the 1.25"-2" clicklock adaptor.

[Stardaze]

1 hour ago, Ricochet said:

Yes, the click lock is excellent, whilst the standard Hexafoc 2" clamp is absolute garbage as it is too shallow. From memory it is something like 2mm of metal, and 8mm clamping ring and then another 2mm of metal. Any sort of undercut on an eyepiece or 1.25"-2" adaptor will result in the original clamp tilting the eyepiece and putting the system out of collimation. 

The only issue you might have is with the resulting focuser being a bit too long or a bit too short. Find the click lock page on Baader's website and there is an image that gives the optical path length for all the different click locks. You can then check at what distance your eyepieces focus (use the scale on the focuser) and, by measuring the height of the 2" clamp and the extension, deduce which combination allows you to focus. With my 8", I removed the extension piece as well as the original clamp. This is a little shorter than the original, and the focuser is racked almost all the way out to focus, plus the only 2" eyepiece I use is lifted out of the clamp by parfocalising rings so that it focuses at the same point as my XWs when they are in the 1.25"-2" clicklock adaptor.

Thanks, I'll get my head around that. Did you go with the click lock yourself, assume there's no cheaper alternatives?

[Ricochet]

1 minute ago, Stardaze said:

Thanks, I'll get my head around that. Did you go with the click lock yourself, assume there's no cheaper alternatives?

No cheaper alternatives as far as I am aware. There wasn't even a Clicklock on the market when I ordered mine. I had to get calipers out and measure the threads on the focuser, and being a prototype, it cost maybe double what you would pay for for the production version. (Mine is actually an M68/1 Clicklock with an M68/1 to M68/0.75 converter ring, I don't know if the production model is the same of M68/0.75 on all threads.)

[Stardaze]

19 minutes ago, Ricochet said:

No cheaper alternatives as far as I am aware. There wasn't even a Clicklock on the market when I ordered mine. I had to get calipers out and measure the threads on the focuser, and being a prototype, it cost maybe double what you would pay for for the production version. (Mine is actually an M68/1 Clicklock with an M68/1 to M68/0.75 converter ring, I don't know if the production model is the same of M68/0.75 on all threads.)

Care to share a pic. How long have you had your Bresser? Pleased with it overall and any more mods?

Edited June 21, 2020 by Stardaze

[Stardaze]

Just measuring up and I think it’s 68mm for mine, this one:

https://www.firstlightoptics.com/adapters/baader-clicklock-m68-clamp-for-hexafoc-focusers-bresser-omegon-and-explore-scientific.html
 

Doesn’t give the additional optical gain but around 30mm looking at other versions? The extension is 40mm, so a gain of around 10mm. Most of my EPs focus around 13-20 (tips out at 42mm) on the focuser so there seems to be plenty of room if the extension is removed?

Edit: The baader website states 43.5. The overall length of the extension is 50mm so should just be a straight swap.

Edited June 21, 2020 by Stardaze

[Ricochet]

6 hours ago, Stardaze said:

Care to share a pic. How long have you had your Bresser? Pleased with it overall and any more mods?

Apparently, I've had it since the end of 2015, which is longer than I would have guessed. Generally I've been happy with it and I've got no plans to replace it with anything else at this time. Modification wise I've done the following: 

• 1.25" and 2" Baader clicklocks on the focuser 
• 3d printed ring on the left focuser wheel to give more control (and it's insulated which is actually nicer to use when it is cold). I will probably put the 10:1 fine focuser on the right hand side even though it isn't strictly necessary. 
• Dob knob fitted using one of the holes where the "lower" RDF shoe was originally. 
• RDF replaced with Telrad and 9x50 RACI. 

• Inside of the tube flocked
• Ring fitted on top of mirror clips to mask the mirror edge and tighten up star images (quite difficult to see as the inside is so dark, the rear of the secondary spider you can see in the top left is actually black). 

• Rear cooling fan. The screws that hold the mirror cell to the OTA have been replaced with longer screws. There is a 3d printed spacer and washer on each screw which allows the fan to be mounted via hair bands to reduce vibrations from the fan being transmitted to the telescope. There is also a baffle to try to force the air from the fan around the mirror and up the tube rather than it just bouncing off the back of the mirror. I've recently fitted some E strip between the baffle and mirror cell to try to prevent any vibration being transmitted that way, but it is yet to be tested.

• Riser fitted to the base so that I can slide the OTA further back in the rings than is possible with the standard base. With a Telrad, 9x50 RACI and binoviewers, this is needed if you don't want to add weight to the mirror end of the tube. 
• Fan controller fitted in the riser to turn the fan down. There is also a 12v battery on the inside of the rocker box. 
• Shedmate feet fitted to lift the base off the ground a little. These have to be set in the lowest position possible or vibrations are not damped sufficiently, they can't be used for levelling in my opinion. 
• Cuphooks to hold the dust cover while the telescope is in use. 

I think that is everything I've done so far. 

5 hours ago, Stardaze said:

The baader website states 43.5. The overall length of the extension is 50mm so should just be a straight swap.

Excellent, sounds like you should be fine then. 

[Stardaze]

58 minutes ago, Ricochet said:

Apparently, I've had it since the end of 2015, which is longer than I would have guessed. Generally I've been happy with it and I've got no plans to replace it with anything else at this time. Modification wise I've done the following: 

• 1.25" and 2" Baader clicklocks on the focuser 
• 3d printed ring on the left focuser wheel to give more control (and it's insulated which is actually nicer to use when it is cold). I will probably put the 10:1 fine focuser on the right hand side even though it isn't strictly necessary. 
• Dob knob fitted using one of the holes where the "lower" RDF shoe was originally. 
• RDF replaced with Telrad and 9x50 RACI. 

• Inside of the tube flocked
• Ring fitted on top of mirror clips to mask the mirror edge and tighten up star images (quite difficult to see as the inside is so dark, the rear of the secondary spider you can see in the top left is actually black). 

• Rear cooling fan. The screws that hold the mirror cell to the OTA have been replaced with longer screws. There is a 3d printed spacer and washer on each screw which allows the fan to be mounted via hair bands to reduce vibrations from the fan being transmitted to the telescope. There is also a baffle to try to force the air from the fan around the mirror and up the tube rather than it just bouncing off the back of the mirror. I've recently fitted some E strip between the baffle and mirror cell to try to prevent any vibration being transmitted that way, but it is yet to be tested.

• Riser fitted to the base so that I can slide the OTA further back in the rings than is possible with the standard base. With a Telrad, 9x50 RACI and binoviewers, this is needed if you don't want to add weight to the mirror end of the tube. 
• Fan controller fitted in the riser to turn the fan down. There is also a 12v battery on the inside of the rocker box. 
• Shedmate feet fitted to lift the base off the ground a little. These have to be set in the lowest position possible or vibrations are not damped sufficiently, they can't be used for levelling in my opinion. 
• Cuphooks to hold the dust cover while the telescope is in use. 

I think that is everything I've done so far. 

Excellent, sounds like you should be fine then. 

Thanks for that. There's a couple of interesting additions there that I hadn't discovered yet, like somewhere for the dust cover and the simple idea of some foam on the carry handles. I don't think a replacement base will be this year now, so I might do that, especially when it's cold!

Also realise that you can't really just replace the 2" EP locking system without doing the 1.25" too. 

What real benefit do you get from the fan, is it solely quicker cool down? How quickly can you cool it in theory? At home, I dont the see a need as seems to take an hour so just need to prepare but taking it somewhere could be different? I need to read more around dew control and gear up for that following my soggy session Friday. Does the rear fan assist there much? 

[Stardaze]

Just googled the feet and a review here made me chuckle 😀

[Ricochet]

1 hour ago, Stardaze said:

What real benefit do you get from the fan, is it solely quicker cool down? How quickly can you cool it in theory? At home, I dont the see a need as seems to take an hour so just need to prepare but taking it somewhere could be different? I need to read more around dew control and gear up for that following my soggy session Friday. Does the rear fan assist there much? 

The fan gives a faster cool down, but I couldn't give an exact time. It really depends on what you are observing and the powers required. 

In terms of dew I have had issues with the secondary dewing up in the past, but since I've fitted the fan I don't think it has happened once and I haven't had to fit a secondary heater. 

48 minutes ago, Stardaze said:

Just googled the feet and a review here made me chuckle 

I think I may have seen that review when I was looking for them. I think I bought mine on eBay for a fraction of the price. 

[Stardaze]

6 minutes ago, Ricochet said:

The fan gives a faster cool down, but I couldn't give an exact time. It really depends on what you are observing and the powers required. 

In terms of dew I have had issues with the secondary dewing up in the past, but since I've fitted the fan I don't think it has happened once and I haven't had to fit a secondary heater. 

I think I may have seen that review when I was looking for them. I think I bought mine on eBay for a fraction of the price. 

Do you run the fan for a time and turn off during viewing? Do you tend to take your dob out away from home?

Edited June 21, 2020 by Stardaze

[Ricochet]

6 minutes ago, Stardaze said:

Do you run the fan for a time and turn off during viewing? Do you tend to take your dob out away from home?

I have been turning it off for high magnification viewing to try to get a more stable image. That is why I have added the e strip to see if fan vibration is reduced. 

With regards to locations, my current work patterns mean that I've hardly had the opportunity to observe from home, let alone to take the scope out to a darker site. 

[Stardaze]

19 minutes ago, Ricochet said:

I have been turning it off for high magnification viewing to try to get a more stable image. That is why I have added the e strip to see if fan vibration is reduced. 

With regards to locations, my current work patterns mean that I've hardly had the opportunity to observe from home, let alone to take the scope out to a darker site. 

Fair enough. Just trying to understand how you use yours and why you've added a fan. Train of thought was that if you take it out a lot you'd probably want to cool it quickly to start. At home there's normally an hour to cool beforehand at this time of year.