267 replies to this topic

[oldmanrick]

The dovetail clamp on my APM "Big Binocular Fork Mount" measures 3.75 inches, (95.25mm) wide when the clamp is open, and 10.25 inches, (260.35mm), long.  The clamp is about 0.25 inch, (6.35mm), narrower when the clamp is completely closed.

 

I made the spacer under the clamp the same width and length as shown above, with the clamp open.  Originally (in the photo) the spacer was a 3/4 inch thick piece of plywood, but I have since made a new spacer to the same dimensions out of solid oak wood and painted it black.

 

The spacer allows the binocular, when properly balanced fore and aft, to be moved to any azimuth position and remain in place with the clutches completely loosened.

 

Rick

[alfaScorpii]

I ordered a "standard" forkmount for my APM 100 SD. But with the dovetail and bar (Vixen/losmandy ?) of the forkmount BIG.

But the dimensions you write (26 cm x 9.5) are huge. I think of the weight of the dovetail + bar.

maybe i need to change the order.

 

I don't understand, however, why you put the "spacer" (oak wood) below the dovetail to balance the binoculars.

can't you slide the bar over the dovetail  to get binocular balance?

[oldmanrick]

Congratulations on your order of the new APM 100 SD!  Looks to be a great instrument.

 

I haven't had my hands on a "standard" fork mount sized for the APM 100 and 120, but being as you are getting a 100, the standard mount should be fine.  I am quite surprised that APM would supply a "big" clamp with the standard mount, due to the much larger scale, and the possible difficulty of mounting it to the base swing plate of that mount.  I use a much lighter Arca style photo type dovetail and clamp to mount my Lunt 100 binocular, which is identical to the APM 100 APO ED.

 

There is no dovetail bar supplied with the "big" fork mount, only a clamp.  The 150 binocular comes with a dovetail foot as its mounting base.  The dovetail clamp grabs onto this base, holding the binocular to the mount.

 

The "Big Binocular Fork Mount" has the clamp bolted to the swinging base plate, and as such is so low that the binocular, when mounted, is situated with its center of gravity lower than the pivot point of the side arms which are bolted to the ends of the base plate.  This means that the weight of the binocular will always try to bring the swinging arms and base plate assembly to the bottom of their travel.

 

The wood spacer simply raises the binocular about 17.8 mm which moves the COG up to the pivot (hinge) point of the swinging assembly.

 

You are right in that the binocular also needs to be positioned fore or aft the proper amount so that it is balanced fore and aft including the weight of the eyepieces and any other equipment being used.  This is done by slightly loosening the clamp and VERY CAREFULLY sliding the binocular forward or back in the clamp until it balances perfectly.

 

This way the binocular / swing arm assembly is balanced in both axes, and will stay put wherever you leave it.

 

Hope this helps!

 

Rick

Edited by oldmanrick, 05 December 2020 - 06:11 PM.

[alfaScorpii]

Thanks. I am happy with the purchase, and I hope to make many good observations of the sky.
Sure, a 100mm is not a 150mm.
Your instrument must be a show for galaxies and nebulae!

 

so, as I understand it, the dovetail foot (4) of the 150 binoculars slides over the clamp (1) bolted to the forkmount's swing base plate. This without the need to use a vixen/losmandy bar (2) to attach to the foot of the binoculars!

 

Edited by alfaScorpii, 06 December 2020 - 09:04 AM.

[oldmanrick]

Correct!

 

If I wanted to mount my Lunt 100 in this mount I would need to use a dovetail bar, as the 100 has no dovetail foot.

 

Rick

[oldmanrick]

At last we had some breaks in the clouds today, which hung around until well after sunset allowing a fleeting look at Jupiter's and Saturn's great conjunction.

 

I rolled out the APM 150 equipped with the UFF 30mm 2" eyepieces, plus a newly assembled Nexus DSC kit from Serge at Astro Devices.

 

I began trying to find the planets just after sunset, with the sky still brightly lit by glowing clouds, low in the SW, near where the planets would be located.  I was unable to find the subjects by scanning the area where they should be, so did a quick and dirty setup of the Nexus based on my best guess of where due South was.  I did level the BT in the 90 degree position using a hand level, so at least the Alt reading would be quite accurate.

 

Took a quick reading of the up-to-the-second position of Jupiter from Sky Safari, and aimed the BT at that spot. At first there was nothing to be seen, but assuming that the instrument was aimed at close to the proper elevation, I began scanning right and left.  On the first scan to the left I found them, both in the same field, only about 2 degrees left of where the Nexus indicated they should be.  The conjunction only spanned about 20% of the 2.6 degree FOV at 28X.  My estimate of due South wasn't bad, being only about 2 degrees off.

 

Seeing was horrible but I wanted a closer view so installed the Morpheus 9mm eyepiece pair, giving 93X.  I still could not see the planets naked eye, so took another reading from Sky Safari.  By this time clouds had moved in front of the planets so had to wait about 1/2 hour before another clear area arrived.  By this time I could see Jupiter naked eye, so just used the red dot finder to line up on the target.  Both planets still easily fit within the 0.82 degree FOV, taking up less than 1/2 of it.

 

At 93X seeing was truly awful, with Jupiter being a big shimmering blob.  Saturn looked slightly better, but still bad, so no photos were attempted.  The weather service had been reporting that we had a strong jet stream overhead, so that must have been the cause of the poor seeing.

 

More thicker clouds were closing in, so I packed up and retreated to the shop for the BT, and the warm house for me.  No photos attempted due to poor seeing.

 

After this very brief first experience in using the Nexus DSC, I am very pleased with it, as it allowed me to quickly find the planets, even without a proper and accurate set up procedure.

 

Rick

[Balenk]

I'm aware binoculars are mostly made to be used visually, but it's always interesting to try to do more (when it's possible). Because the APM 150 are quite a big boy, it's not a problem to adapt a full frame camera on it. So, I plugged my Pentax K1 and with a basic 2x SVbony barlow, I could reach the focus point and take some pictures of the recent giant planet's conjunction. Here is the result.

 

I took several "one shot" pictures, to adapt the light and get the planets and the satellites together. I had to fight with my home-made mount, not at all made for such a work (ok in visual, but far to be enough stable to focus properly in Liveview mode), so I'm ok with the result.

Edited by Balenk, 24 December 2020 - 03:08 AM.

[oldmanrick]

Balenk,

 

Wow very nice!  Looks like you even got Titan in a couple of shots.  Jupiters moons are splendid!

 

I tried a commercial, mostly plastic adapter for my i-phone but got frustrated with it and returned it.  It didn't grip any of the eyepieces properly that I tried it on, and of course trying to focus messed everything up to where I had to start over.  I've been looking for a better holder/adapter, as I would really like to be able to reliably shoot photos through one side of the 150.

 

Thanks for sharing!

 

Rick

[Balenk]

Thank you, Rick. To plug the Pentax in the APM, I used a T-ring (K mount), a M42 to 1,25" adapter, a 1,25" barlow 2x (needed to reach the focus) and the native APM 2" to 1,25" eyepiece holder. I own most of these pieces, then I used them, but it should be better if you can avoid the 2" --> 1,25" part of it : T-ring, M42 to 2", 2" barlow x2 (or more) in the APM 2" eyepiece. Now that I'm sure it works, I'll do it again !

 

(BTW, something went wrong in my previous link. Here are my images)

Edited by Balenk, 25 December 2020 - 03:06 AM.

[Rich56]

Do you find that observing with eyepieces that are 45 degrees bent are a hassle at times?

If one is using this for mainly astro targets that 90 degree bends would be better if they were available.

[oldmanrick]

Do you find that observing with eyepieces that are 45 degrees bent are a hassle at times?

If one is using this for mainly astro targets that 90 degree bends would be better if they were available.

Yes, especially when viewing above about 60 to 70 degrees.  A support with a vertical gear driven column helps a lot at high viewing angles, but it still becomes a pain in the neck if viewing for long periods.  It's also a hassle for terrestrial viewing in mountainous terrain if you need to look downward at a very steep angle.

 

My BT viewing is a combination of astro and terrestrial, with a lot of it being the latter, so the 45 degree eyepiece angle is better for me.

 

There are several BT models available having 90 degree eyepiece mounting, including the new APM 150mm SD, with better glass.  I have seen no observer reports on this one yet.  It is somewhat more expensive than the APM 150 APO ED model that I own.

 

Rick

[ArsMachina]

There are several BT models available having 90 degree eyepiece mounting, including the new APM 150mm SD, with better glass.  I have seen no observer reports on this one yet.  It is somewhat more expensive than the APM 150 APO ED model that I own.

They are still not available ...

 

Jochen

[oldmanrick]

My mistake Jochen, I understand that just because the 90 degree SD 150 can be ordered doesn't mean it's "available".  You will probably be one of the first to get one, if not the first.  That also explains why I haven't read any user reports yet.

 

Hopefully there will be some soon!

 

Rick 

[ArsMachina]

There are some few and unofficially but very promising reports form Markus himself and some people who had the chance to look through the prototype at a telescope meeting this summer.

But I am still waiting for a call from Markus every day to jump into my car and bring that baby home  :-)

 

And for sure the crowd will know this the very same day :-)

 

Jochen

[Balenk]

Do you find that observing with eyepieces that are 45 degrees bent are a hassle at times?

If one is using this for mainly astro targets that 90 degree bends would be better if they were available.

45 degrees bent binoculars, for a near exclusive astronomical use... it's obviously not the best choice. But I didn't hesitate to buy the 150ED 45° anyway : I previously owned Nikon 20x120, which are straight, and I learned to deal with it. As concerns high targets (let's say 75° or more), if your mount doesn't allow you to observe comfortably, you just have to wait : except if you live under a polar sky, at some point, these targets will go down.

[garret]

 

But I am still waiting for a call from Markus every day to jump into my car and bring that baby home

"Lieferbar ab 15 Januari, 2021"

[oldmanrick]

As mentioned previously in this thread, I decided sometime back, to investigate adding a "digital setting circles" aiming system to the APM Big Binocular Fork Mount presently holding the APM 150 BT.

 

First choice to contact concerning availability or development of a kit for this mount was Serge at Astro Devices in Australia.  Shortly after sending an email to Serge, I received a phone call from him indicating that the could put together a kit for me that would fit my mount.  He requested that I provide some measurements of critical components of the mount so he could make the necessary parts to the dimensions needed to fit properly, as he did not have access to a copy of the mount.

 

After several communications back and forth by phone and email, providing additional measurements needed and detailed photos of the mount and critical parts, I received very complete kit, very well packaged, in the mail.

 

The kit consisted of the Nexus keyboard/display/computer unit;  a mounting plate to hold this unit;  a shoulder bolt replacing one of the bolts holding the fixed upright arm of the mount to the base plate of the mount, to support the mounting plate for the Nexus unit;  digital magnetic rings for altitude and azimuth readings;  plastic housings containing readers to read the magnetic circles;  one tiny metal bar with threaded screw holes and screws to mount the plastic housing for the azimuth reader to the channelled slot in the bottom of the mount base bar, (the altitude reader housing slips snugly into the wide slot in the fixed upright arm of the mount, and is held securely in place by two-sided tape under the wings of the housing);  two sets of "Y" cables to go from the readers to the Nexus unit;  several stick-on plastic cable clips;  a battery charger with charging cable;  and two instruction books, one a quick-view and the other a complete instruction book.

 

The two magnetic circles were mounted snugly in plastic rings sized to fit over the round support pedestal of the mount, for the azimuth circle, and over the round bearing block at the top of the fixed arm of the mount, for the altitude circle.  Unfortunately, the altitude circle plastic ring was a bit loose in its fit to the round block, and also had to be slid out so much that it was overhanging the outer edge of the block to line up with the reader well enough to get a reliable accurate reading.

 

More communications with Serge resulted in him voluntarily agreeing to re-make the elevation circle mounting ring to slightly smaller tolerances. I was able to get the original ring to fit snugly enough by wrapping one layer of plastic electrical tape around the altitude bearing block, but Serge thought it was better to make a new mounting ring.  He also made a new mounting block for the altitude reader to move the reader closer to the center of the magnetic ring without overhang.

 

These new parts fit very well and I completed assembly and testing of the system successfully.

 

The whole process from my first email until completion took several months.  Due to the corona virus pandemic during this time, causing an increase in orders for products from Astro Devices, Serge had gotten very busy.  I'm sure that without the virus, the process would have gone much more quickly.  Astro Devices and Serge have been very good to do business with, and the cost to me for this was similar to comparable kits already developed and ready to sell at Astro Devices.  I highly recommend them and their products.

 

So far my use of this system has been very limited, but preliminary indications are that it will be a very useful tool for me.  It will allow me to find difficult targets in the night sky, plus help identify other interesting objects that I stumble upon while scanning the sky.  There will be a learning curve for me to be able to get the most out of this system, but that will have to wait until warmer weather and clear skies.

 

Here are some photos of the system installed.

 

 

Here you can see the shoulder bolt that attaches the Nexus base to the mount.

 

 

 

This shows the Nexus unit, altitude ring and reader.

 

 

 

This one shows the altitude ring, reader, cabling, Nexus mount, and Nexus DSC. 

 

 

 

Rick

Edited by oldmanrick, 28 December 2020 - 04:54 PM.

[ArsMachina]

That is really great Rick!

 

I also thought about digital setting circles but do not want cables and mechanical attachments.

So I am patiently waiting until a completely wireless and non mechanical system comes out.

Things are going but not ready yet:

 

https://www.youtube....eature=emb_logo

 

Jochen