Hi. I enjoy solar observing, but will be new to solar imaging. I have a Lunt Solar LS80THa that is double stacked, with a 12 mm blocking filter, a Televue 2X PowerMate, and an ASI6200MM camera which is overkill from a sensor size perspective but is great for deep sky imaging. The LS80THa is f/7, so after the 2X PowerMate I would be critically sampled for the ASI6200MM's 3.76 um pixels at 656 nm and f/14. So all good, but...
The solar full disc image will be 10.4 mm diameter, so it plus prominences would need ~2900 x 2900 of those 3.76 um pixels. I have Firecapture, but am currently at a different property than the camera and scope, and so can't test the supported ROI flexibility. The ASI spec sheet only mentions rectangular ROIs, and the only one of those exceeding 2900 in its shortest dimension is 6400×4096, which is slow at 7.44fps. Does Firecapture support arbitrary square ROIs on the ASI6200MM, such that I could dial in 2900 x 2900, and if so, what would the fps be? The smaller sensor ASI533MM has 3008 x 3008 pixels, pretty close, also 3.76 um, and it claims a full resolution frame rate of 19.88 fps. Would the smaller ASI533MM actually provide a higher FPS than an ROI on the ASI6200MM, and if so, by how much?
None of these FPS would be anywhere near the 100 Hz range for a full solar disc, and I get that higher FPS improves the odds for lucky imaging, but 12 mm sensors at high frame rates are pricey; one such option would be a 25 GigE "Bolt" camera from Emergent Vision Technologies with the Sony IMX531 sensor (2.74 um pixels, 4504 x 4504 pixels, 12.3 mm square, up to 100 fps at full resolution, 112 fps @ 4000 x 4000; link below), but that seems like overkill and expensive, also a bit oversampled at f/14 (4.1X instead of 3X).
How much of a compromise would 10 to 20 FPS be, if I was ready to discard capture frames or sequences that had bad seeing in them? Wouldn't I eventually "get lucky" even at these lower frame rates?
Last bit: I have read snippets here that adding a Barlow (so maybe also the telecentric PowerMates) will result in Newton's rings. Is that true, and if so, what are my options? Thanks in advance!
All the best,
Edited by Coconuts, 11 August 2022 - 06:23 AM.