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Kevin:

Not sure what model you have and what you mean by "tests", but I have a 12-inch Sky-Watcher 300P GoTo, WiFi controllable scope. It gets transported A LOT - in the back of a pickup, and I rarely, if ever, run into collimation issues.

I transport the OTA laying on its side in the original large cardboard box it was shipped in (see attached). I put 5-inches of soft foam in the box, under the OTA to absorb any sudden jolts.

After you collimate the primary, there are "lock-down" knobs next to the collimation knobs that you tighten down. This "locks the collimation in place". After I lock down my collimation, I seem to have little to no collimation issues. Are your mirror clips loose?
My 2ndary has never needed re-collimation in the several years I've had it.

I do my collimation with just a standard laser collimator - see attached.

Also....
If yours is a GoTo and WiFi capable, forget the bulky SynScan hand controller and use the SynScan app for Android phones - and control the scope via the WiFi app (it's MUCH easier).

After a "north level", and 2 star alignment, I just type in the RA & DEC of my Target Star and the scope almost always slews itself to within 1 camera FOV of the Target.

Other "mods" I did....
* I designed my own motorized focuser (via a gear motor)
* I added a 2nd place to put the finder - on the metal tube that also holds the mirror
* Added resistors to the back of the 2ndary as an anti-dew unit
* Stuck a bubble level to the base
* Built a 3-wheel dolly to move it around the yard, and out to my truck (rough weight of the scope is about 100lbs - 50 for the OTA, 50 for the base). The dolly saves my back!

George

Our tests with our 12" Skywatcher have yet to be successful. I will be picking up my Astrid tomorrow, Saturday, so maybe that will help.

One issue we've had is that the scope gets out of collimation when travelling. Two questions:

(1) How do you keep the vibrations low when in transit so the mirrors stay aligned?
(2) Is there a preferred collimator? I clearly need to get one.

Like Kevin, I have been sending new light curves from the PyOTE VizieR tab, as requested by Dave Herald a while back. Do it after the North American report form and it will populate the Light Curve information automatically.

I've been uploading all new light curves straight from PY-OTE. Happy to answer any questions. It is easier to finish the NA xlsx report form first, because the detector information can be uploaded from that. The other thing is trimming the light curve so that the dip is seen.

There is the intention of going back and uploading all my prior observations. Will do so at some point.

Generally, I agree with George that it would be better to have more information available, but I don't think VizieR is the place for that. Instead, a general IOTA repository makes more sense. Occult-4 is that to some extent, but it is missing some of the details, like the fit information.

?

Steve / Kevin:

Probably best to put the question on the IOTA Groups.io. Dave Herald will probably answer it - but ask for details in how to do it and if he wants Comparison Stars included.

G

Steve:

I know this is something that Dave Herald has been pushing for, and to date I haven't looked into it much. Wish I could help on the procedure, but I don't know it.
However.... ever since PyMovie/PyOTE came out I have been including a screenshot of my light curve(s) with my report anyway - so a light curve will always be available for my observation.
That said, it's my feeling that supplying just the sole light curve of my Target Star is "worthless" -- without including the light curve of at least one Comparison Star near the Target. The inclusion of a Comparison Star , I feel, notably adds "validity" to the claimed event.
In PyMovie you can display both the plots of the Target Star and a "Composite Plot" [Target Star, Comparison Star(s), Background Measurement]. I "stack" them and then do a screen capture (Windows Key + Shift + S). I'll often "expand the Target Star plot a bit also.
Below is a sample using an occultation I captured last night (July 2 UT).
I really do feel at least 1 Comparison Star should (/must) be included in any light curve that is submitted -- but that's my 2-cents.

George

Roxanne:

Yes, you can use your Astrid in a (very) manual mode. In the upper left of the camera control interface, under the exposure & gain settings, just enter a short text [maybe something like "(5441)" so that your video file will have an ID for asteroid (5441), and then when you want to record, just press the circular button under the ID. It will change from a dark gray(?) to red to indicate you are recording. Press the same button again to halt the recording. This is what I do 95% of the time when I'm using Astrid "attended". I find entering info from an OW file 'nice' but actually a bit of a nuisance sometimes.

...And if you forget to put a new text in and press record again later, you WON'T overwrite the original file - since the time of the recording will also be in a part of the filename.

Let us know if you have further questions. Maybe we can help.

G

Ted has one more Astrid, so I'm going to get one to try it out.

Great to see the group. I learned a few things that will be useful going forward. I loaded Skype onto my iPad for a better experience.

A good 2-hour long discussion among 5 NEUS folks - Steve, Rick, Roxanne, Kevin G., and myself.
Skype worked nicely... No need for a paid Zoom account.
Hope folks felt it was worth getting Northeast folks together to trade notes.......
??? -G

NEUS Folks,

Steve and I are planning an informal chat for this Wed eve 6/26 at 7:30pm (the time is SET). Other NEUS folks are welcome to sit in. I'm setting it up, and for me, part of the reason for the chat is to test out Skype/Meet Now (owned by MicroSoft) as a meeting platform. Skype works very similar to Zoom, is free, and has -NO- time limit. I believe you also don't need to have the Skype/Meet Now app on your computer. I've used Skype often before but not for more than a 2-person chat...?
To join-in, send me an email and I will send you the link to get in (this avoids any "gate-crashers" if the link is made public).?
To attend, all you have to do is click on the link. My email address is..... [Email address edited off after the chat session was over].
We'll probably cover Astrid, flashers, mobile site selection, recruitment, etc....

George

Hi,

George,

Steve (and Rick):

Thx for the thoughts.

As for "next steps"... I think I'm done with flasher 'testing' for now.?
I have more magnitude tests waiting to process - magnitude depth vs exposure for several scopes. It's a very good thing to know... how deep you can reach with a certain scope given a certain exposure. Seeing as I have 3 cameras and 8 scopes (20, 14.5, 12, 8, 6, 4.5, 3, 135mm) and my list includes about 25 different exposure settings.... Ouch!?
I'm about half way done with that.

But as far as general testing for someone who gets a flash timer and already has a "pretty-picture camera" (that is video capable)... There are a number of folks near me that have such cameras and I have hoped that someday they might consider getting a flash timer and try an occasional occultation. [After all, astronomy is a SCIENCE, not an ART FORM]. In which case I could test their flasher against perhaps my Astrid - and at least "certify" that their flasher is up to spec. But as for an individual's camera system.... that would probably remain a wild card. It's possible (tho somewhat difficult) to test that, but so far I haven't needed to go that route..... Since they are still stubbornly ignorant of doing any real science and too wound-up doing their "astro-art".?
'Guess that may be their "plateau".

As for some other questions.........
* In my test videos, could I see a slope?
Attached are typical sample light curves for two of the tests presented in the prior post (tests 5 & 9). In each image the top plot just shows the Target Star and its simulated occultation. As you can see, the simulation is very much what you would see in a real event (with a quick deep drop - and recovery). Any fading is VERY minimal.
The bottom plot shows both the Target and the "Flash Sense" (a Static PyMovie aperture with the "white aperture" chosen).?

What's interesting to note in these plots is the variation in light intensity of the "Flash Sense" aperture - especially in test 9! You will note that one video has almost a "square-wave" variation in its "baseline" for the "Flash Sense". This is caused by an automatic gain stage kicking in and out in the actual sensor chip of the Astrid. I sometimes also see this with my RunCams. The actual sensors in both the Astrid and RunCams have this "build-in automatic gain switching" and it is NOT something that can be disabled in any camera control software. It's simply how the sensor works. Sometimes this can be seen visually on a monitor. At times it "behaves itself" and the automatic gain switching is minimal, but it seems if the light on the sensor is near a certain "threshold", it can cause the sensor's gain to continually jump between two different settings.
Note that you only see this "jumping" in the PyMovie aperture that is set to sense the flash (a Static white aperture). You will note that in the light of the Target Star, the gain jumping is "absent". This is because in PyMovie for each individual frame of video of the Target Star, PyMovie calculates, then subtracts-out the background level. This effectively "removes" the gain jump. For the white aperture which senses the flash, no background level is subtracted out (so as the gain jumps up, so does the background level!).
But even with the "gain jumping" in the "Flash Sense" white aperture, PyOTE can still accurately determine the leading edge of the flash.

You asked...
* "What happens to one of Aart's flashers if they have dicey GPS reception? ?I think he logs such things, but is a new user going to understand they have to check the log..."
In the log my flasher creates it logs the number of GPS satellites used. I just looked at the log for the 12 tests I presented above and at a minimum I see "Sats: 12" and at a maximum I see "Sats: 18". So yes.... a flash user (if they want to do things right) should consult their log files. I believe 4 or 5 satellites for most GPS time devices is satisfactory. A dozen or more is almost overkill.

You asked...
* "Do you know what GPS receiver is on your Adafruit shield board?"
No. If I get the opportunity to check I'll let you know.

You asked...
* Any idea what testing Aart has done?
I just know that Aart and John Moore have done extensive testing. Some time last year I presented them with my test results and the reply I got was...... "Yeah, we know that... We've already done it".

SEXTA.... Thanks, but I'm done with flash testing on my unit. It's "proven". Need to run mag tests next and get those videos off my hard drive (all these tests are taking up a serious percentage of the space on my hard drive!!).

You asked...
* "Are you planning to present your results at the IOTA meeting in September?"
Not unless I feel like punishing myself. I'm sure there would be a few hard-line 'denouncers' of using flash timing (irregardless of any situation) and I'd get their wrath.
Which leads me to saying (/repeat)...........

I ALWAYS would advocate that folks use per frame GPS timestamping as the proper way to time, but... I DO feel using flash timers "have their place" in our 'sport'.......

* First, as Rick mentioned, it can be an inexpensive way for folks to get started in occultations. With flashers, the cost to get started in occultations apparently may be under $100 (if they already own a video-capable "pretty-picture camera"). ...and as Steve mentioned, it seems very soon (if not now) assembled Astrids will be available. Right now, they seem to be the cheapest "occultation-ready" camera that can be bought --- but the cost is $700+ with shipping(!). I know of some observers who - without question - won't spring for that to start out.

...And now let's discuss another aspect... HOW GOOD IS GOOD ENOUGH?
Do we always record our occultation videos at 30fps? Answer - NO. Sometimes the Target Star is quite faint and we may need to record at 4fps. So in that case, even if someone uses a flasher which references NTP, and which has an inherent [tested] "inaccuracy" of 0.01 seconds, that "inaccuracy" is still 1/25th of the frame rate that is being recorded(!). ...and yes, remember PyMovie can do timing to sub-frame accuracy (to some extent). So in such a case, I'd say that even flash timing based on NTP might be quite valid for a camera recording at 4fps.
So... In short...?
I feel that the timing method really needs to be selected/evaluated based on each individual occultation event.

Also..........
Consider the case where an experienced observer sets out to record an event (perhaps using an Astrid - ie, timestamps). But... He knows another observer who mainly does "astro-art" (they are intent on taking the 40 millionth picture of M13), and he [----!!somehow!!----] persuades them to set aside their "astro-art" for a moment...... and use a GPS-based flash timer to also time the event (some distance away).
Consider... Without the additional flash timing, the experienced observer would only get ONE CHORD on the asteroid.
But if the 2nd observer (flash timer) also gets a chord, and both observers report their events, now you [potentially] have TWO CHORDS on the same event.
Which brings up an important point..........
When an occultation gets reported, one of the things that gets asked on the report form is... "What was your timing source?"
So the experienced observer reports that he used his Astrid (which has GPS-based timestamps on every frame of video).
The inexperienced observer reports that he used a GPS-based flash timer. [And the experienced observer does the analysis of his video].
It's very important that the timing device be clearly noted in EVERY report. There should be the choice in our report forms which includes flash timing, and the sub-categories of...
* Flash Timing - GPS based
* Flash Timing - NTP based
So when it comes to determining the "chords" for the asteroid, much more "weight" could (should?) be given to the chord obtained via the Astrid, vs the chord obtained via the Flash Timer. If there's a large discrepancy --- Simply throw out the chord obtained by the flash timer.?
But... If they "fit", now you have a much more valuable observation -- you now how TWO CHORDS where there may have been just ONE!
So what was gained by using a Flash Timer?.... A SECOND CHORD!

Sorry for the novel.

George

Steve:
Triple Congrats on the multi-station deploy! ...and great that you got Hits at all stations!
Thanks for the story too... Fun reading about such efforts.?
Looks like Tom should have been in the shadow too - hope it worked out for him.
I like the last hour "creative solution" aspect (using the finderscope at your observatory). Likewise, I've had to Gerry-rig many last minute solutions in the field.
BTW I have a nice shot at (1852) Carpenter on the 16th. I'll be going mobile to put myself right on the centerline. The shadow runs from me to right over Buffalo to Cleveland (a bit west of you - but maybe possible for Tom?). Mag 11.9 for 1.65 sec. I'm considering trying a 2nd station.
Anyway...... Thanks for the story and Congrats!
? ?-G